This document describes the design of new DNA-based fluorescent nanodevices that act as pH sensors with expanded sensitivity. The nanodevices use DNA i-motifs that undergo a conformational change between an i-motif structure at acidic pH and a duplex structure at basic pH. By incorporating chemically modified cytosines into the i-motif region, the researchers were able to tune the pH sensitivity range of the nanodevices. They created versions with brominated or methylated cytosines in different positions, and found that some achieved a collective sensing range from pH 5.3 to 7.5. The modified nanodevices also exhibited much larger signal changes between the two conformations, resulting in improved dynamic range for pH sensing.
The document summarizes characterization of the H134C mutant of the Thermus thermophilus Rieske protein. Key findings include:
1) The H134C mutant substitutes one ligating histidine for a cysteine, changing the iron-sulfur cluster ligation from 2Cys-2His to 3Cys-1His.
2) Studies using UV-visible spectroscopy, circular dichroism, and reaction with diethyl pyrocarbonate (DEPC) show the H134C mutant is stable across a wide pH range, unlike the similar mitochondrial protein mitoNEET.
3) Reaction of H134C with DEPC results in modification of the cluster but no reduction,
This document presents a kinetic method for determining microquantities of D(-)-arabinose. The method relies on D(-)-arabinose accelerating the reaction between molybdenum(VI) and hydrogen peroxide in a 50% acetonitrile solution. Optimal experimental conditions were determined by studying the kinetics of this reaction with and without D(-)-arabinose. D(-)-Arabinose concentrations from 46 to 135 μg/ml were determined photometrically by measuring the rate of colored product formation. The standard deviation was less than 10%. This kinetic method allows for the determination of microquantities of D(-)-arabinose.
SIMONA CAVALU_Raman and surface-enhanced Raman spectroscopy of tempyo spin la...Simona Cavalu
Tempyo labelled ovalbumin at different pH values was prepared and investigated using Raman and SERS spectroscopy.
Raman spectra of tempyo labelled ovalbumin in the pH range from 6.7 to 11 were compared to those of the corresponding free
ovalbumin. In the basic pH range from 6.7 to 11 the molecular conformation was found to be unaffected by the tempyo
presence. Adsorption versatility to the colloidal Ag particles of pure- and tempyo labelled ovalbumin was also found to be
unchanged in this basic pH range. As the SERS binding site of protein the a-helix conformation is favourable.
This document summarizes an investigation into using an enzymatic catalyst to catalyze the esterification of telechelic polymers, specifically poly(butadiene) and poly(ethylene oxide), in order to generate macromolecular chain transfer agents (CTAs) for synthesizing block copolymers. Experiments were conducted to esterify a hydroxyl-functionalized poly(butadiene) with a carboxylic acid functional RAFT agent using Novozym 435 catalyst. NMR and GPC analysis indicated some esterification occurred, though the molecular weight increase was small. More investigation is needed to optimize the reaction conditions to fully synthesize the macromolecular CTA. The goal is to develop a mild method to
1) Lipases are water-soluble enzymes that catalyze the hydrolysis of ester bonds in triacylglycerols and belong to the alpha/beta hydrolase fold family. They contain a catalytic triad of Ser-His-Asp/Glu and undergo conformational changes through a flexible lid region.
2) Lipases exist in both closed and open conformations, with the closed state shielding the active site and the open state exposing a hydrophobic surface upon lid movement. This lids movement is important for catalytic activity and binding to interfaces.
3) Molecular modeling was used to study the reaction mechanism and conformational preferences of Candida antarctica lipase B. The results supported a
Facile Syntheses of Substituted, Conformationally-Constrained Benzoxazocines ...JamesSahn
A multicomponent assembly process (MCAP) was utilized to prepare versatile intermediates that are suitably functionalized for subsequent cyclizations via Ullmann and Heck reactions to efficiently construct substituted 2,6-methanobenzo[b][1,5]oxazocines and 1,6-methanobenzo[c]azocines, respectively. The intramolecular Ullmann cyclization was conducted in tandem with an intermolecular arylation that enabled the rapid syntheses of a number of O-functionalized methanobenzoxazocines.
Source: Tetrahedron Lett. 2011 December 21; 52(51): 6855–6858.
1) Burst phase kinetic analysis was used to evaluate the rate of deamination (k3) of the aminated−methyl-idene imidazolone (NH2−MIO) adduct in the Taxus phenylalanine aminomutase (TcPAM) enzyme.
2) The analysis showed that TcPAM forms a transient NH2−MIO adduct during catalysis, resulting in an initial burst of product formation followed by a slower steady-state rate.
3) The deamination rate of the NH2−MIO adduct (k3 = 0.041 ± 0.002 s−1) was determined, demonstrating that the adduct and subsequent reaction
The document summarizes characterization of the H134C mutant of the Thermus thermophilus Rieske protein. Key findings include:
1) The H134C mutant substitutes one ligating histidine for a cysteine, changing the iron-sulfur cluster ligation from 2Cys-2His to 3Cys-1His.
2) Studies using UV-visible spectroscopy, circular dichroism, and reaction with diethyl pyrocarbonate (DEPC) show the H134C mutant is stable across a wide pH range, unlike the similar mitochondrial protein mitoNEET.
3) Reaction of H134C with DEPC results in modification of the cluster but no reduction,
This document presents a kinetic method for determining microquantities of D(-)-arabinose. The method relies on D(-)-arabinose accelerating the reaction between molybdenum(VI) and hydrogen peroxide in a 50% acetonitrile solution. Optimal experimental conditions were determined by studying the kinetics of this reaction with and without D(-)-arabinose. D(-)-Arabinose concentrations from 46 to 135 μg/ml were determined photometrically by measuring the rate of colored product formation. The standard deviation was less than 10%. This kinetic method allows for the determination of microquantities of D(-)-arabinose.
SIMONA CAVALU_Raman and surface-enhanced Raman spectroscopy of tempyo spin la...Simona Cavalu
Tempyo labelled ovalbumin at different pH values was prepared and investigated using Raman and SERS spectroscopy.
Raman spectra of tempyo labelled ovalbumin in the pH range from 6.7 to 11 were compared to those of the corresponding free
ovalbumin. In the basic pH range from 6.7 to 11 the molecular conformation was found to be unaffected by the tempyo
presence. Adsorption versatility to the colloidal Ag particles of pure- and tempyo labelled ovalbumin was also found to be
unchanged in this basic pH range. As the SERS binding site of protein the a-helix conformation is favourable.
This document summarizes an investigation into using an enzymatic catalyst to catalyze the esterification of telechelic polymers, specifically poly(butadiene) and poly(ethylene oxide), in order to generate macromolecular chain transfer agents (CTAs) for synthesizing block copolymers. Experiments were conducted to esterify a hydroxyl-functionalized poly(butadiene) with a carboxylic acid functional RAFT agent using Novozym 435 catalyst. NMR and GPC analysis indicated some esterification occurred, though the molecular weight increase was small. More investigation is needed to optimize the reaction conditions to fully synthesize the macromolecular CTA. The goal is to develop a mild method to
1) Lipases are water-soluble enzymes that catalyze the hydrolysis of ester bonds in triacylglycerols and belong to the alpha/beta hydrolase fold family. They contain a catalytic triad of Ser-His-Asp/Glu and undergo conformational changes through a flexible lid region.
2) Lipases exist in both closed and open conformations, with the closed state shielding the active site and the open state exposing a hydrophobic surface upon lid movement. This lids movement is important for catalytic activity and binding to interfaces.
3) Molecular modeling was used to study the reaction mechanism and conformational preferences of Candida antarctica lipase B. The results supported a
Facile Syntheses of Substituted, Conformationally-Constrained Benzoxazocines ...JamesSahn
A multicomponent assembly process (MCAP) was utilized to prepare versatile intermediates that are suitably functionalized for subsequent cyclizations via Ullmann and Heck reactions to efficiently construct substituted 2,6-methanobenzo[b][1,5]oxazocines and 1,6-methanobenzo[c]azocines, respectively. The intramolecular Ullmann cyclization was conducted in tandem with an intermolecular arylation that enabled the rapid syntheses of a number of O-functionalized methanobenzoxazocines.
Source: Tetrahedron Lett. 2011 December 21; 52(51): 6855–6858.
1) Burst phase kinetic analysis was used to evaluate the rate of deamination (k3) of the aminated−methyl-idene imidazolone (NH2−MIO) adduct in the Taxus phenylalanine aminomutase (TcPAM) enzyme.
2) The analysis showed that TcPAM forms a transient NH2−MIO adduct during catalysis, resulting in an initial burst of product formation followed by a slower steady-state rate.
3) The deamination rate of the NH2−MIO adduct (k3 = 0.041 ± 0.002 s−1) was determined, demonstrating that the adduct and subsequent reaction
This study investigated the phosphorylation of α-synuclein (α-Syn), a protein implicated in Parkinson's disease, using NMR spectroscopy. α-Syn has three domains and adopts different structural assemblies during its aggregation process. Phosphorylation may contribute to α-Syn aggregation, though the mechanisms are unclear. The study used NMR to monitor the activity of CK2α, a kinase known to phosphorylate α-Syn at Ser129. Preliminary results found CK2α phosphorylated α-Syn as observed by biochemical analysis and minor chemical shift changes in NMR spectra. Future work will further characterize the effects of phosphorylation on α-Syn aggregation in both buffer and cell lysates using techniques like NMR, fluorescence,
The document summarizes a study examining the effects of mutations to amino acids asparagine 284 and tryptophan 246 in the human adenosine A2a receptor (hA2aR). The study found that mutating these amino acids completely abolished hA2aR signaling function, as cyclic AMP (cAMP) levels were undetectable in cells expressing the mutant receptors. While wild type hA2aR increased cAMP levels when stimulated with adenosine, the allosteric modulator amiloride further elevated cAMP levels, suggesting it acts as a positive modulator of hA2aR. The mutations did not affect inverse agonist binding. The results indicate these amino
enzyme kinetics, mechanism of action of enzymes and line-weaver burk plotmuti ullah
This document discusses key concepts in enzyme kinetics including:
Vmax represents the maximum initial rate of a catalyzed reaction when all enzyme is saturated with substrate. Km is the substrate concentration at which the reaction rate is at half of Vmax, and 50% of enzyme is bound to substrate. A Line-Weaver Burk plot can be used to determine Km and Vmax values from experimental data by taking the inverse of reaction rates and substrate concentrations.
This document describes the design, synthesis, and evaluation of novel thrombin inhibitors incorporating P3-P4 lactam sulfonamide moieties. The inhibitors were designed to exploit interactions with thrombin's S2 and S3 sites to improve selectivity over related serine proteases. A series of 5-7 membered lactam rings were synthesized and incorporated a P1 argininal group. X-ray crystallography of one inhibitor bound to thrombin confirmed the predicted binding mode. In vitro testing showed several inhibitors had low nanomolar IC50 values against thrombin and good selectivity over trypsin and factor Xa. Overall, the lactam sulfonamides represent a new class of orally bioavailable
This document summarizes the synthesis and characterization of two new Ru(II),Rh(III),Ru(II) trimetallic complexes containing selectively deuterated ligands. NMR spectroscopy of the deuterated complexes allows for better structural assignment compared to the undeuterated variants. The deuterated complexes show identical ground state properties but increased excited state lifetime and emission quantum yield, indicating decreased nonradiative decay. Previous studies found deuterated bimetallic complexes to be more efficient for photocatalytic hydrogen production. Studying the deuterated trimetallics aims to further understand and improve their mechanism for photocatalytic water reduction.
This document summarizes an experiment aiming to identify the RNA-binding domain of the human LARP6 protein. The researcher expressed and purified constructs of LARP6 containing residues 70-300 and 70-313. While purification of the SUMO tag was successful, the LARP6 portions degraded. As a control, the SUMO tag alone showed non-specific binding to test RNAs. Future work will optimize expression and purification conditions to prevent degradation and characterize RNA binding of intact LARP6 constructs.
SIMONA CAVALU_Raman and Surface Enhanced Raman Spectroscopy of 2,2,5,5-Tetram...Simona Cavalu
ABSTRACT: 2,2,5,5-Tetramethyl-3-pyrrolin-1-yloxy-3-carboxamide (tempyo) labeled bovine
serum albumin and cytochrome c at different pH values were prepared and
investigated using Raman–resonance Raman (RR) spectroscopy and surface enhanced
Raman scattering (SERS) spectroscopy. The Raman spectra of tempyo labeled proteins
in the pH 6.7–11 range were compared to those of the corresponding free species. The
SERS spectra were interpreted in terms of the structural changes of the tempyo labeled
proteins adsorbed on the silver colloidal surface. The tempyo spin label was found to be
inactive in the Raman–RR and SERS spectra of the proteins. The a-helix conformation
was concluded to be more favorable as the SERS binding site of bovine serumalbumin.
In the cytochrome c the enhancement of the bands assigned to the porphyrin macrocycle
stretching mode allowed the supposition of the N-adsorption onto the colloidal surface.
This study investigated the polymerization of lactic acid as a model for prebiotic peptide formation via ester-amide exchange. Lactic acid was polymerized in a closed system at 85°C over various time points. HPLC and 1H-NMR were used to analyze the polymers and determine degree of polymerization (DP) and total lactic acid units. DP was found to increase with time while total units decreased, showing polymer regeneration. Methods showed consistent results within 10-15% error. Further studies will compare kinetics to a computer simulation to determine rate constants and model polymerization from various monomers.
This document summarizes a patent for novel steroid compounds and processes for preparing them. Specifically, it describes compounds having the formula A5-3-ethylenedioxy-cyclopentanopolyhydrophenanthrene and processes for converting them to 11-dehydrocorticosterone via intermediate iodo, keto, and acetoxy compounds. An example reaction is provided to synthesize 11-dehydrocorticosterone from a starting iodo compound.
The document describes using reversible addition-fragmentation chain transfer (RAFT) polymerization to synthesize novel block copolymers containing both a polyolefin block and a poly(styrene-co-maleic anhydride) block. Specifically, it details:
1) Using a commercially available polyolefin (Kraton L-1203) modified with a dithioester group to serve as a macroinitiator for RAFT polymerization and form the polyolefin block.
2) Conducting RAFT polymerizations of styrene and styrene-co-maleic anhydride using this macroinitiator and a small molecule RAFT agent to form the second block and yield polyolefin
A Fluorescent Probe Designed For Conformational Studiessubbu2681
The document describes the design and testing of a fluorescent probe called Amino Phenoxazone Maleimide (APM) to study protein conformational changes. APM was used to label and monitor two membrane proteins: a voltage-gated potassium channel and the beta-2 adrenergic receptor. APM was shown to report on known conformational changes in these proteins and had advantages over other fluorescent probes like having less interference from cellular autofluorescence.
The document summarizes research conducted by Alejandro Gil Villegas of the University of Guanajuato's Department of Physical Engineering on predicting phase diagrams of fluids using thermodynamic perturbation theory and Monte Carlo simulations. Some key points:
- The research combines thermodynamic perturbation theory and Monte Carlo simulations to predict phase diagrams of mixtures of fluids.
- Gil Villegas' department offers degrees in physics, physical engineering, chemical engineering, and biomedical engineering at both the undergraduate and postgraduate levels.
- The research focuses on associating fluids, using theories like SAFT (Statistical Associating Fluid Theory) to model interactions.
- Applications include modeling asphaltene precipitation and predicting phase equ
This document summarizes a study investigating the initialization behavior of reversible addition-fragmentation chain transfer (RAFT)-mediated styrene-maleic anhydride copolymerizations using in situ 1H NMR spectroscopy. The results indicate specificity of addition of the RAFT agent leaving groups for either styrene or maleic anhydride. Analysis of the NMR spectra also showed that monomers are added individually, favoring the penultimate unit model of polymer propagation over other proposed mechanisms. Stereoselectivity was observed during monomer addition to the RAFT agent.
Studies of transition metal ion - 5- Sulphosalicylic acid doped PolyanilinesIOSR Journals
This document summarizes a study on transition metal ion-5-sulphosalicylic acid complexes used as dopants for polyaniline. Polyaniline was doped with various transition metal carbonates both with and without 5-sulphosalicylic acid. The doped polyanilines were characterized through various tests. Conductivity was found to increase with increasing acid concentration in the doping solution. Magnetic susceptibility measurements showed paramagnetic behavior for transition metal-doped polyanilines and diamagnetic behavior for polyaniline doped with only 5-sulphosalicylic acid. The polymers were found to be amorphous by XRD. SEM showed small
1. The document describes peptides designed to mimic the discontinuous VEGF receptor-binding site on VEGF, which is important for VEGF's angiogenic properties.
2. Two peptide fragments from different regions of VEGF that interact with the receptor were synthesized and joined together with amino acid linkers of varying lengths.
3. Testing showed the joined peptides promoted VEGF receptor phosphorylation in cells and stimulated angiogenesis signaling pathways, similarly to native VEGF, with the longest linker peptide being most potent. This suggests the peptides can modulate the angiogenic response by mimicking VEGF's receptor interaction.
1) Researchers developed a method to controllably form grain boundary PbI2 nanoplates that passivate CH3NH3PbI3 and CH3NH3PbI2Br perovskite films.
2) The PbI2-passivated perovskite films were prepared via direct reaction of hydrohalide-deficient PbI2 xHI/Br precursors with CH3NH2 gas, followed by annealing.
3) The amount of PbI2 impurities could be controlled by adjusting the hydrohalide deficiency in the precursors. Solar cells made with the PbI2-passivated perovskites showed higher efficiencies than those without
This document summarizes the synthesis of novel 3'-C-methylene thymidine, 5-methyluridine, and 5-methylcytidine H-phosphonates and phosphonamidites for modifying the backbone of oligonucleotides. The key intermediates 3'-C-iodomethyl nucleosides were reacted with in situ generated bis(trimethylsilyl)phosphite (BTSP) using modified Arbuzov reaction conditions to directly obtain the desired 5'-O-DMT and MMT protected 3'-C-methylene modified H-phosphonates without removing protecting groups. Some phosphonates were further converted to corresponding phosphonamidite monomers through a one-pot multi
Cooperative learning in science education is addressed in this article. How students use a very relevant topic of anti-cancer agents, and the novel technique of (Heteronuclear single Quantum Correllation Spectroscopy )2D -HSQC FT-NMR to organize spectra data is shown. Here, undergraduates become familiar with making plots of 1H FT-NMR and 13C FT-NMR , learning FT-NMR data processing (spinworks) and also use Chemdraw NMR to present data take with a Varian 600 MHz FT-NMR spectrometer.
ATP synthase is an enzyme that generates ATP from ADP and inorganic phosphate using energy from the proton gradient across the inner mitochondrial membrane. It consists of two main parts - F0, which forms a channel for protons to pass through, and F1, which contains the catalytic sites to synthesize ATP. The passage of protons through F0 powers the rotation of F1, which facilitates the formation of ATP from ADP and phosphate at three catalytic binding sites. The overall reaction catalyzed by ATP synthase couples proton translocation across the membrane to ATP synthesis, and is essential for energy production in cells.
Photocatalytic reduction of carbon dioxide to methanol using a ruthenium trin...Pawan Kumar
This document summarizes the photocatalytic reduction of carbon dioxide to methanol using a ruthenium trinuclear polyazine complex immobilized on graphene oxide under visible light irradiation. Specifically:
- A ruthenium complex was synthesized and immobilized on graphene oxide through complexation. This developed photocatalyst was used to reduce CO2 to methanol under visible light irradiation.
- After 48 hours of illumination, the yield of methanol was 3977.57 mmol/gcat, higher than for graphene oxide alone. The catalyst could be reused without loss of activity.
- Characterization showed the ruthenium complex was successfully immobilized on the graphene oxide support, enhancing its photocatalytic activity and enabling
This study investigated the phosphorylation of α-synuclein (α-Syn), a protein implicated in Parkinson's disease, using NMR spectroscopy. α-Syn has three domains and adopts different structural assemblies during its aggregation process. Phosphorylation may contribute to α-Syn aggregation, though the mechanisms are unclear. The study used NMR to monitor the activity of CK2α, a kinase known to phosphorylate α-Syn at Ser129. Preliminary results found CK2α phosphorylated α-Syn as observed by biochemical analysis and minor chemical shift changes in NMR spectra. Future work will further characterize the effects of phosphorylation on α-Syn aggregation in both buffer and cell lysates using techniques like NMR, fluorescence,
The document summarizes a study examining the effects of mutations to amino acids asparagine 284 and tryptophan 246 in the human adenosine A2a receptor (hA2aR). The study found that mutating these amino acids completely abolished hA2aR signaling function, as cyclic AMP (cAMP) levels were undetectable in cells expressing the mutant receptors. While wild type hA2aR increased cAMP levels when stimulated with adenosine, the allosteric modulator amiloride further elevated cAMP levels, suggesting it acts as a positive modulator of hA2aR. The mutations did not affect inverse agonist binding. The results indicate these amino
enzyme kinetics, mechanism of action of enzymes and line-weaver burk plotmuti ullah
This document discusses key concepts in enzyme kinetics including:
Vmax represents the maximum initial rate of a catalyzed reaction when all enzyme is saturated with substrate. Km is the substrate concentration at which the reaction rate is at half of Vmax, and 50% of enzyme is bound to substrate. A Line-Weaver Burk plot can be used to determine Km and Vmax values from experimental data by taking the inverse of reaction rates and substrate concentrations.
This document describes the design, synthesis, and evaluation of novel thrombin inhibitors incorporating P3-P4 lactam sulfonamide moieties. The inhibitors were designed to exploit interactions with thrombin's S2 and S3 sites to improve selectivity over related serine proteases. A series of 5-7 membered lactam rings were synthesized and incorporated a P1 argininal group. X-ray crystallography of one inhibitor bound to thrombin confirmed the predicted binding mode. In vitro testing showed several inhibitors had low nanomolar IC50 values against thrombin and good selectivity over trypsin and factor Xa. Overall, the lactam sulfonamides represent a new class of orally bioavailable
This document summarizes the synthesis and characterization of two new Ru(II),Rh(III),Ru(II) trimetallic complexes containing selectively deuterated ligands. NMR spectroscopy of the deuterated complexes allows for better structural assignment compared to the undeuterated variants. The deuterated complexes show identical ground state properties but increased excited state lifetime and emission quantum yield, indicating decreased nonradiative decay. Previous studies found deuterated bimetallic complexes to be more efficient for photocatalytic hydrogen production. Studying the deuterated trimetallics aims to further understand and improve their mechanism for photocatalytic water reduction.
This document summarizes an experiment aiming to identify the RNA-binding domain of the human LARP6 protein. The researcher expressed and purified constructs of LARP6 containing residues 70-300 and 70-313. While purification of the SUMO tag was successful, the LARP6 portions degraded. As a control, the SUMO tag alone showed non-specific binding to test RNAs. Future work will optimize expression and purification conditions to prevent degradation and characterize RNA binding of intact LARP6 constructs.
SIMONA CAVALU_Raman and Surface Enhanced Raman Spectroscopy of 2,2,5,5-Tetram...Simona Cavalu
ABSTRACT: 2,2,5,5-Tetramethyl-3-pyrrolin-1-yloxy-3-carboxamide (tempyo) labeled bovine
serum albumin and cytochrome c at different pH values were prepared and
investigated using Raman–resonance Raman (RR) spectroscopy and surface enhanced
Raman scattering (SERS) spectroscopy. The Raman spectra of tempyo labeled proteins
in the pH 6.7–11 range were compared to those of the corresponding free species. The
SERS spectra were interpreted in terms of the structural changes of the tempyo labeled
proteins adsorbed on the silver colloidal surface. The tempyo spin label was found to be
inactive in the Raman–RR and SERS spectra of the proteins. The a-helix conformation
was concluded to be more favorable as the SERS binding site of bovine serumalbumin.
In the cytochrome c the enhancement of the bands assigned to the porphyrin macrocycle
stretching mode allowed the supposition of the N-adsorption onto the colloidal surface.
This study investigated the polymerization of lactic acid as a model for prebiotic peptide formation via ester-amide exchange. Lactic acid was polymerized in a closed system at 85°C over various time points. HPLC and 1H-NMR were used to analyze the polymers and determine degree of polymerization (DP) and total lactic acid units. DP was found to increase with time while total units decreased, showing polymer regeneration. Methods showed consistent results within 10-15% error. Further studies will compare kinetics to a computer simulation to determine rate constants and model polymerization from various monomers.
This document summarizes a patent for novel steroid compounds and processes for preparing them. Specifically, it describes compounds having the formula A5-3-ethylenedioxy-cyclopentanopolyhydrophenanthrene and processes for converting them to 11-dehydrocorticosterone via intermediate iodo, keto, and acetoxy compounds. An example reaction is provided to synthesize 11-dehydrocorticosterone from a starting iodo compound.
The document describes using reversible addition-fragmentation chain transfer (RAFT) polymerization to synthesize novel block copolymers containing both a polyolefin block and a poly(styrene-co-maleic anhydride) block. Specifically, it details:
1) Using a commercially available polyolefin (Kraton L-1203) modified with a dithioester group to serve as a macroinitiator for RAFT polymerization and form the polyolefin block.
2) Conducting RAFT polymerizations of styrene and styrene-co-maleic anhydride using this macroinitiator and a small molecule RAFT agent to form the second block and yield polyolefin
A Fluorescent Probe Designed For Conformational Studiessubbu2681
The document describes the design and testing of a fluorescent probe called Amino Phenoxazone Maleimide (APM) to study protein conformational changes. APM was used to label and monitor two membrane proteins: a voltage-gated potassium channel and the beta-2 adrenergic receptor. APM was shown to report on known conformational changes in these proteins and had advantages over other fluorescent probes like having less interference from cellular autofluorescence.
The document summarizes research conducted by Alejandro Gil Villegas of the University of Guanajuato's Department of Physical Engineering on predicting phase diagrams of fluids using thermodynamic perturbation theory and Monte Carlo simulations. Some key points:
- The research combines thermodynamic perturbation theory and Monte Carlo simulations to predict phase diagrams of mixtures of fluids.
- Gil Villegas' department offers degrees in physics, physical engineering, chemical engineering, and biomedical engineering at both the undergraduate and postgraduate levels.
- The research focuses on associating fluids, using theories like SAFT (Statistical Associating Fluid Theory) to model interactions.
- Applications include modeling asphaltene precipitation and predicting phase equ
This document summarizes a study investigating the initialization behavior of reversible addition-fragmentation chain transfer (RAFT)-mediated styrene-maleic anhydride copolymerizations using in situ 1H NMR spectroscopy. The results indicate specificity of addition of the RAFT agent leaving groups for either styrene or maleic anhydride. Analysis of the NMR spectra also showed that monomers are added individually, favoring the penultimate unit model of polymer propagation over other proposed mechanisms. Stereoselectivity was observed during monomer addition to the RAFT agent.
Studies of transition metal ion - 5- Sulphosalicylic acid doped PolyanilinesIOSR Journals
This document summarizes a study on transition metal ion-5-sulphosalicylic acid complexes used as dopants for polyaniline. Polyaniline was doped with various transition metal carbonates both with and without 5-sulphosalicylic acid. The doped polyanilines were characterized through various tests. Conductivity was found to increase with increasing acid concentration in the doping solution. Magnetic susceptibility measurements showed paramagnetic behavior for transition metal-doped polyanilines and diamagnetic behavior for polyaniline doped with only 5-sulphosalicylic acid. The polymers were found to be amorphous by XRD. SEM showed small
1. The document describes peptides designed to mimic the discontinuous VEGF receptor-binding site on VEGF, which is important for VEGF's angiogenic properties.
2. Two peptide fragments from different regions of VEGF that interact with the receptor were synthesized and joined together with amino acid linkers of varying lengths.
3. Testing showed the joined peptides promoted VEGF receptor phosphorylation in cells and stimulated angiogenesis signaling pathways, similarly to native VEGF, with the longest linker peptide being most potent. This suggests the peptides can modulate the angiogenic response by mimicking VEGF's receptor interaction.
1) Researchers developed a method to controllably form grain boundary PbI2 nanoplates that passivate CH3NH3PbI3 and CH3NH3PbI2Br perovskite films.
2) The PbI2-passivated perovskite films were prepared via direct reaction of hydrohalide-deficient PbI2 xHI/Br precursors with CH3NH2 gas, followed by annealing.
3) The amount of PbI2 impurities could be controlled by adjusting the hydrohalide deficiency in the precursors. Solar cells made with the PbI2-passivated perovskites showed higher efficiencies than those without
This document summarizes the synthesis of novel 3'-C-methylene thymidine, 5-methyluridine, and 5-methylcytidine H-phosphonates and phosphonamidites for modifying the backbone of oligonucleotides. The key intermediates 3'-C-iodomethyl nucleosides were reacted with in situ generated bis(trimethylsilyl)phosphite (BTSP) using modified Arbuzov reaction conditions to directly obtain the desired 5'-O-DMT and MMT protected 3'-C-methylene modified H-phosphonates without removing protecting groups. Some phosphonates were further converted to corresponding phosphonamidite monomers through a one-pot multi
Cooperative learning in science education is addressed in this article. How students use a very relevant topic of anti-cancer agents, and the novel technique of (Heteronuclear single Quantum Correllation Spectroscopy )2D -HSQC FT-NMR to organize spectra data is shown. Here, undergraduates become familiar with making plots of 1H FT-NMR and 13C FT-NMR , learning FT-NMR data processing (spinworks) and also use Chemdraw NMR to present data take with a Varian 600 MHz FT-NMR spectrometer.
ATP synthase is an enzyme that generates ATP from ADP and inorganic phosphate using energy from the proton gradient across the inner mitochondrial membrane. It consists of two main parts - F0, which forms a channel for protons to pass through, and F1, which contains the catalytic sites to synthesize ATP. The passage of protons through F0 powers the rotation of F1, which facilitates the formation of ATP from ADP and phosphate at three catalytic binding sites. The overall reaction catalyzed by ATP synthase couples proton translocation across the membrane to ATP synthesis, and is essential for energy production in cells.
Photocatalytic reduction of carbon dioxide to methanol using a ruthenium trin...Pawan Kumar
This document summarizes the photocatalytic reduction of carbon dioxide to methanol using a ruthenium trinuclear polyazine complex immobilized on graphene oxide under visible light irradiation. Specifically:
- A ruthenium complex was synthesized and immobilized on graphene oxide through complexation. This developed photocatalyst was used to reduce CO2 to methanol under visible light irradiation.
- After 48 hours of illumination, the yield of methanol was 3977.57 mmol/gcat, higher than for graphene oxide alone. The catalyst could be reused without loss of activity.
- Characterization showed the ruthenium complex was successfully immobilized on the graphene oxide support, enhancing its photocatalytic activity and enabling
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
Recombinant antibody mediated delivery of organelle-specific DNA pH sensors a...saheli halder
This document describes the development of a new family of DNA pH sensors that can be targeted to specific intracellular locations using recombinant antibodies. The sensors incorporate a "handle" domain that binds recombinant antibodies identified through a phage display screen. One such antibody is fused to the membrane protein furin, allowing the sensors to be ferried along the furin endocytic pathway inside living cells. By changing the sequence of the pH sensitive domain, sensors were created that span pH ranges from 4 to 7.6. When targeted to cells expressing the antibody-furin chimera, the sensors map the spatiotemporal pH changes within intracellular compartments during furin trafficking. This targeting technique provides a generalizable strategy for delivering DNA nanode
A pH-independent DNA nanodevice for quantifying chloride transport in organel...saheli halder
This document describes a DNA nanodevice called Clensor that can precisely measure chloride ion concentration in organelles of living cells in a pH-independent manner. Clensor consists of sensing, normalizing, and targeting modules and uses a ratiometric fluorescence approach to quantify chloride levels across the full physiological range. The authors demonstrate that Clensor can be used to measure resting chloride concentration in lysosomes of Drosophila cells and show that lysosomal chloride is regulated by the intracellular chloride transporter DmClC-b.
This resume summarizes Angela M. Rickelm's qualifications for a substance abuse counselor position. She has over 5 years of experience as a substance abuse counselor in Illinois and Texas, facilitating individual and group sessions, conducting assessments, and developing treatment plans. She holds a Bachelor's degree in Psychology and is a Certified Reciprocal AODA Counselor. She also has research experience in psychology and teaching experience as a teaching assistant.
Technological devices have become part of the everyday classroom. The teacher is able to use technology to help with interactive lessons as well as having access to online resources.
This one sentence document does not provide enough context or information to create an accurate 3 sentence summary. The document contains only one word - "Lorem" - which is not meaningful on its own.
tuning the pH Response of i-Motif DNA Oligonucleotides_Lannes_et_al-2015-Chem...saheli halder
This document discusses tuning the pH response of i-motif DNA oligonucleotides. The authors introduced 5-methylcytosines (5-MeC) and 5-bromocytosines (5-BrC) into the human telomeric i-motif sequence to shift its pH response range. They found that 5-MeC shifted the pH response towards more basic values, while 5-BrC shifted it towards more acidic values. Additionally, lengthening the sequence shifted the pH response in a more basic direction. The modifications did not thermally destabilize the i-motifs. 5-BrC substitution led to a ten-fold increase in folding kinetics compared to the other sequences.
La acción de tutela es un mecanismo de protección constitucional de los derechos fundamentales de los colombianos. Procede contra particulares cuando estos prestan un servicio público, afectan grave y directamente un interés colectivo, o cuando existe un estado de subordinación o indefensión hacia el afectado. También procede contra particulares que ejercen funciones públicas, pues en tal caso ostentan la calidad de autoridad pública.
This short document outlines two compositions by González Templos Bryan. It lists "Composition 1" and "Composition 2" but provides no further details about the pieces.
Este documento describe los primeros auxilios para heridas y quemaduras en la piel. Explica cómo clasificar heridas y quemaduras según su gravedad y profundidad, desde lesiones leves de primer grado hasta graves de tercer grado. Detalla los pasos básicos para el cuidado inicial de ambos tipos de lesiones, como limpiar y desinfectar la herida, enfriar una quemadura, aplicar apósitos estériles y buscar atención médica para las lesiones graves.
This document provides a career summary and background for Harish Kumar Mohan. It outlines his 14+ years of experience in software development for areas including Linux drivers, wireless/embedded systems, and mobile devices. It details his technical skills and experience building applications for Qualcomm, Motorola, Verizon Wireless, and other companies. His education includes a Master's in Wireless and Embedded Systems from UCSD and a Master's in Computer Science from Madras University in India.
This document describes a study that used a modified NMR experiment called SOLEXSY to measure intrinsic amide proton exchange rates (kint) for a dynamic loop in the protein chymotrypsin inhibitor 2 (CI2) in buffer and in E. coli cell lysates. The study found that kint values did not change significantly when CI2 was crowded with up to 100 g/L of E. coli lysate. This suggests that kint values measured in buffer experiments can be applied to studies conducted under cellular conditions in the presence of macromolecular crowding.
This document summarizes a study that analyzed the kinetics of proton transport by the M2 protein channel from influenza A virus. The researchers found that proton flux through M2 follows Michaelis-Menten kinetics with two saturation steps around pH 5.5 and pH 4. They determined rate constants and apparent pKa values that matched the pKa values of the histidine residues in M2 that were previously observed. Mutagenesis studies identified residues important for proton entrance, relay, and exit rates. NMR experiments showed synchronized conformational changes between the histidine and tryptophan gate residues during activation.
1) A new fluorescent receptor (compound 3) was designed and synthesized based on an acridine-imidazolium functionalized cholestane for anion sensing.
2) Binding studies using UV-vis and fluorescence spectroscopy showed that compound 3 has the highest selectivity for hydrogen pyrophosphate (HP2O7^3-) with a binding constant of 1.5 x 10^4 M^-1.
3) Molecular modeling showed that HP2O7^3- binds more strongly to compound 3 than other anions through hydrogen bonding interactions between its oxygen atoms and amino and imidazolium hydrogen atoms on the receptor.
This study used NMR spectroscopy to measure hydrogen exchange rates of backbone amide protons in two disordered proteins, a-synuclein and FlgM, in buffer and inside Escherichia coli cells. The rates were similar in buffer and cells, and close to rates predicted from studies of unstructured peptides. This suggests that true disorder can persist inside the crowded cellular interior, and that weak interactions between proteins and macromolecules in cells do not necessarily affect intrinsic exchange rates. However, the C-terminal region of FlgM showed some evidence of transient structure formation in buffer that was not observed inside cells.
The document describes a proposed study to develop a novel class of photoswitchable carboxylic acids whose acidity can be reversibly controlled by light. Dithienylethene compounds will be synthesized that can switch between open and closed states with different light wavelengths. The closed state is expected to be more conjugated, allowing electron donating/withdrawing substituents to influence acidity. Quantum calculations and acidity comparisons will predict acidity changes between states. Target compounds will be synthesized and characterized, with acidity measurements used to validate light-controlled changes. If successful, these photoswitchable acids could enable new applications in catalysis, biochemistry, and more.
Bis-pyrene probes of foldamer conformation in solution and in phospholipid bi...madhu740653
The document describes the design and synthesis of bis(pyrene) fluorescent probes to report on conformational changes in membrane-active peptide foldamers. Several generations of probes were developed and tested, with the most promising being N-acetyl-1,2-bis(pyren-10-yl)ethylenediamine. This probe showed changes in the ratio of excimer to monomer fluorescence emission depending on the screw-sense conformation of the foldamer in solution, allowing conformational changes to be detected. The probe was also able to investigate how the chirality of phospholipids affects foldamer conformation when incorporated into bilayers, providing a sensitive fluorescent reporter for studying foldamers in a membrane environment
Mechanism of the Reaction of Plasma Albumin with Formaldehyde in Ethanol - Wa...IOSR Journals
The Spectrophotometric determination of the acid dissociation/ionisation constant (pKa) of plasma albumin-formaldehyde adduct in both water solution and Ethanol solutions was carried out in this study. The pKa values obtained in both media were used to establish the Bronsted-linear type constants from plots of pKa against logarithm of second order rate constants obtained at varying pHs in the study. The result of the pKa values obtained in both water solution and ethanol-water mixtures were found to be in the range of 5.0 - 8.0. This pointed to the fact that only lysine residue with pKa value 8.3 that might have possibly reacted with formaldehyde in this reaction of all the known amino acid residues in plasma albumin. The corresponding Brønsted-type plots proportionality constants (β) for the reaction in water and ethanol-water mixtures were found to be β = 0.059 and 0.0057 respectively. The reaction mechanisms that have low values for proportionality constants α or β are considered to have a transition state closely resembling the reactant with little proton transfer (Cox et al, 1988). Thus, one would suggest that the cross-linking of formaldehyde with plasma albumin in water and ethanol-water mixtures proceeds through little proton transfer
Comparing the Effects of Different Osmolytes in the B-to-Z DNA TransitionCharlotte C
Hydration of the double helix plays an important role in the conformational transition from right handed B-DNA to left handed Z-DNA, which may be a switch in regulating genetic expression. The Z-DNA conformer is more sparsely hydrated and has a larger solvent exposure of the nonpolar base-pair surfaces. We tested the transitional effects of multiple osmolytes with varying degrees of hydrophobicity.
This document summarizes a study that measured the enthalpy change (ΔH) associated with the α-helix to random coil transition of an alanine peptide in water using calorimetry. The researchers synthesized a 50-residue peptide containing primarily alanine residues and determined its ΔH to be between 0.9-1.3 kcal/mol per residue, providing a basic parameter for predicting thermal unfolding of peptide helices. Circular dichroism spectra and melting curves confirmed the peptide adopted an α-helical structure at low temperatures and underwent a reversible helix-coil transition. The ΔH value suggests the peptide backbone, rather than side chains, makes the dominant contribution to helix stability.
This document summarizes a study that used density functional theory calculations to examine how substituents and gold catalysts influence the reaction pathways of gold-catalyzed cycloisomerization of 1,5-enynes. The study found that with an AuCl catalyst and simplest 1,5-enyne substrate, the pathway involving intramolecular hydrogen shift from C3 to C2 to form a bicyclo[3.1.0]hexane product was both kinetically and thermodynamically favored. Introduction of different substituents or use of a [AuPH3]+ catalyst was found to affect the relative energies of reaction pathways.
Lab 3 acid base titration curves and acid_base indicatorsAnas Maghayreh
1. The document describes an experiment on acid-base titration curves using strong acids (H2SO4) and weak acids (CH3COOH) with a strong base (NaOH). Phenolphthalein and methyl orange indicators were used to determine the equivalence points.
2. Titration curves were generated by measuring the pH at increasing volumes of NaOH added. The equivalence points occurred at a pH of around 8-10 depending on the acid and indicator used.
3. Sources of error in the experiment included reading errors, issues with pH measurement, and not cleaning dishes properly between trials. The experiment demonstrated the use of indicators to find equivalence points in acid-base titrations.
SIMONA CAVALU_EPR study of non covalent spin labeled serum albumin and haemog...Simona Cavalu
Abstract
Electron Paramagnetic Resonance (EPR) was used to investigate the Tempyo spin label (3-carbamoyl-2,2,5,5-
tetramethyl-3-pyrrolin-1-yloxy) as a report group for the interactions and the conformational changes of lyophilized
bovine serum albumin (BSA) and bovine hemoglobin (BH), as function of pH values in the range 2.5–11. The EPR
spectra are similar with those of other non-covalently spin label porphyrins in frozen solution at very low temperatures.
This behavior indicated a possible spin–spin interaction between the hemic iron and the nitroxide group. The changes
in the EPR spectra as function of the pH are discussed in terms of conformational changes of the proteins. Spectral
simulations and magnetic EPR parameters reveal the following: (i) one single paramagnetic species, with Gaussian
line shape, was used for the best fits of experimental spectra in the case of serum albumin samples; and (ii) a
weighted sum of Lorentzian and Gaussian line shape in the case of hemoglobin samples. The representation of
correlation time vs. pH, reveals a dependence of degree of immobilization of spin label on the conformational changes
of proteins in acidic and basic environment.
This document summarizes the total synthesis of 2,6-dideoxy-2,6-imino-7-O-β-D-glucopyranosyl-D-glycero-L-gulo-heptitol hydrochloride (8), a potent inhibitor of α-glucosidases. The key steps involve homologation and amination of 2,3,4,6-tetra-O-benzyl-D-glucopyranose (1) to form the protected amine 4. An intramolecular cyclization of 4 catalyzed by mercuric acetate formed the piperidine ring. Glycosylation of aglycon 6 with acetob
This document describes the total synthesis of 2,6-dideoxy-2,6-imino-7-O-β-D-glucopyranosyl-D-glycero-L-gulo-heptitol hydrochloride (8), a potent inhibitor of α-glucosidases. The key steps involve homologation of D-glucose to form the aglycon, amination to replace the ring oxygen, and glycosylation to attach a glucose moiety. The stereoselective cyclization of an intermediate sets the stereochemistry of the ring junctions. Compound 8 inhibits intestinal sucrase and other glucosidases and lowers postprandial blood glucose in
1) Novel compounds called O,O-diethyl 1-benzamido-2,2-biscarbamoylethanephosphonates were synthesized as substrates for HIV-1 protease (PR) to exploit activation of the phosphonate group.
2) One compound, O,O-diethyl 1-benzamido-2,2-bis[(1S)-N-(1-benzyl-2-hydroxyethyl)carbamoyl]ethanephosphonate, showed moderate anti-HIV activity in vitro. Its depsipeptide analogue inhibited HIV-1 PR with an IC50 of 31 μM.
3) The phosphonate group of these compounds was designed
Proton euilibria in minor groove of dnamganguly123
1) The document describes an experiment testing the prediction that regions of increased hydrogen ion density exist in the grooves of DNA. Probes with variable linker lengths and a proton-sensitive carboxyl group were attached to DNA in the minor groove.
2) The apparent pKa values of the carboxyl groups were higher than in free solution, increasing with shorter linker lengths. This agrees with calculations showing higher hydrogen ion density in the grooves.
3) The experiment provides experimental evidence supporting the theoretical prediction of acidic domains with elevated hydrogen ion density in the DNA minor groove.
The document summarizes the determination of acid dissociation constants (pKa) for several organic compounds using UV-Vis spectrophotometry. It discusses acid-base theory, factors that affect pKa, and the biological importance of pKa values. The method involves taking UV-Vis absorbance scans of compound solutions across a range of pH values. An isosbestic point is identified and used to select an absorption wavelength for analyzing the pH-absorbance curve in GraphPad Prism software. This yields the pKa value from the Boltzmann sigmoidal fit. Determining pKa is important for understanding a compound's properties, metabolism, and suitability as a dye or probe.
The document discusses the use of solid-state NMR spectroscopy and fluorescence spectroscopy to determine the structure and membrane location of pH-low insertion peptides (pHLIPs) under different pH conditions. The results show that at pH 5.3, pHLIPs insert into the lipid bilayer as a transmembrane helix with residues A10 and A13 located near the phosphate groups. At pH 7.4, pHLIPs bind to the membrane surface with a non-helical conformation. At pH 6.4, there is a mixture of membrane-inserted and surface-bound states. These findings provide insight into pHLIPs' pH-dependent conformational changes and membrane insertion behavior.
This study investigated the effects of substituting the native haem group in iNOS with mesohaem, which has a higher electron density. The goals were to dissect the structural and electronic effects on iNOS catalysis. Key findings include:
1) iNOS and the W188H mutant with mesohaem substitution were stable and dimeric, and had similar substrate binding affinities as their native haem counterparts.
2) Single turnover kinetic experiments showed mesohaem substitution triggered higher rates of dioxygen conversion and altered other kinetic parameters.
3) The first crystal structure of iNOS with mesohaem substitution showed essentially identical features to native iNOS, indicating electronic effects primarily influence kinetics rather
The document discusses testing the reactivity between various Good's buffers and vernadite (δ-Mn(IV)O2). X-ray diffraction analysis found structural modifications to vernadite when reacted with EPPS, MOPSO, HEPES, and MOPS buffers, indicating partial reduction of Mn(IV) to Mn(III). The inertness of BES may be due to its molecular geometry lacking nitrogen-containing rings found in the other buffers. Diffraction patterns of vernadite reacted with varying concentrations of MOPS and EPPS showed stacking order was not directly proportional to buffer concentration.
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