Ribozymes are RNA molecules that can catalyze biochemical reactions similar to protein enzymes. They were first discovered in the 1960s and 1970s through the work of Cech, Altman, and others. Ribozymes exist in all living organisms and play important roles in processing transfer and ribosomal RNA. They exhibit a diverse range of structures and catalytic mechanisms despite being composed only of the four nitrogen bases. Common types of ribozymes include hammerhead, hairpin, hepatitis delta virus, and RNase P ribozymes. Ribozymes have potential applications as tools to target specific mRNAs for research and therapeutic purposes.
A ribozyme is a ribonucleic acid (RNA) enzyme that catalyzes a chemical reaction. The ribozyme catalyses specific reactions in a similar way to that of protein enzymes. Also called catalytic RNA, ribozymes are found in the ribosome where they join amino acids together to form protein chains.
Arabinose Operon is a self-regulatory sequence of genes used by material to metabolize a five-carbon sugar called arabinose when there is a deficiency of glucose in the environment.
A ribozyme is a ribonucleic acid (RNA) enzyme that catalyzes a chemical reaction. The ribozyme catalyses specific reactions in a similar way to that of protein enzymes. Also called catalytic RNA, ribozymes are found in the ribosome where they join amino acids together to form protein chains.
Arabinose Operon is a self-regulatory sequence of genes used by material to metabolize a five-carbon sugar called arabinose when there is a deficiency of glucose in the environment.
De novo and salvage pathway of nucleotides synthesis.pptx✨M.A kawish Ⓜ️
This slides explains Metabolism topic "De novo and salvage pathway of nucleotides synthesis. In which synthesis of Purines and pyrimidines synthesis has been occurred. In last there is a difference between these two pathways.
Most bacteria are free-living organisms that grow by increasing
in mass and then divide by binary fission.
Growth and division are controlled by genes, the expression
of which must be regulated appropriately. Genes
whose activity is controlled in response to the needs of a
cell or organism are called regulated genes. All organisms
also have a large number of genes whose products
are essential to the normal functioning of a growing and
dividing cell, no matter what the conditions are. These
genes are always active in growing cells and are known as
constitutive genes or housekeeping genes; examples include
genes that code for the enzymes needed for protein
synthesis and glucose metabolism. Note that all genes are
regulated on some level. If normal cell function is impaired
for some reason, the expression of all genes, including
constitutive genes, is reduced by regulatory
mechanisms. Thus, the distinction between regulated
and constitutive genes is somewhat arbitrary.
This ppt describes the overview of enzyme regulation and Allosterism. Presented since October 23,2017GC at Addis Ababa University, School of Medicine, Department of medical biochemistry.
SOS response was discovered by Miroslav Radman. It's a part of DNA repair system- synthesizes enzymes required for DNA repair. Cellular response to UV damage.
Multienzyme System: A complex of enzymes within a cell that form a reaction sequence of a biochemical pathway so that the product of the first enzyme reaction is transferred directly to the next enzyme and immediately undergoes a second reaction, and so on.
A ribozyme is a ribonucleic acid (RNA) enzyme that catalyses specific reactions in a similar way to that of protein enzymes; it also known as catalytic RNA, ribozymes are found in the ribosome for protein formation and play a role in other vital mechanisms such as RNA splicing, transfer RNA biosynthesis, and viral replication. Discovery of catalytic RNA contributed to the hypothesis of prebiotic RNA world i.e. how life may have originated from an “RNA World” inhabited by self-replicating ribozymes. The ribosome is indeed a ribozyme underlines the relevance of RNA catalysis in today’s protein-dominated world.
The recent discoveries of RNA interference and micro-RNA associated mechanisms of gene regulation further emphasize the central importance of RNA to understanding gene regulation and leads to design new RNA-based technologies for gene manipulation and silencing.
The discovery that riboswitches and in some cases ribozymes, including a variant of the hammerhead ribozyme are also involved in regulating gene expression explains how intimately RNA structure, function, and catalysis are involved in many aspects of biological control.
De novo and salvage pathway of nucleotides synthesis.pptx✨M.A kawish Ⓜ️
This slides explains Metabolism topic "De novo and salvage pathway of nucleotides synthesis. In which synthesis of Purines and pyrimidines synthesis has been occurred. In last there is a difference between these two pathways.
Most bacteria are free-living organisms that grow by increasing
in mass and then divide by binary fission.
Growth and division are controlled by genes, the expression
of which must be regulated appropriately. Genes
whose activity is controlled in response to the needs of a
cell or organism are called regulated genes. All organisms
also have a large number of genes whose products
are essential to the normal functioning of a growing and
dividing cell, no matter what the conditions are. These
genes are always active in growing cells and are known as
constitutive genes or housekeeping genes; examples include
genes that code for the enzymes needed for protein
synthesis and glucose metabolism. Note that all genes are
regulated on some level. If normal cell function is impaired
for some reason, the expression of all genes, including
constitutive genes, is reduced by regulatory
mechanisms. Thus, the distinction between regulated
and constitutive genes is somewhat arbitrary.
This ppt describes the overview of enzyme regulation and Allosterism. Presented since October 23,2017GC at Addis Ababa University, School of Medicine, Department of medical biochemistry.
SOS response was discovered by Miroslav Radman. It's a part of DNA repair system- synthesizes enzymes required for DNA repair. Cellular response to UV damage.
Multienzyme System: A complex of enzymes within a cell that form a reaction sequence of a biochemical pathway so that the product of the first enzyme reaction is transferred directly to the next enzyme and immediately undergoes a second reaction, and so on.
A ribozyme is a ribonucleic acid (RNA) enzyme that catalyses specific reactions in a similar way to that of protein enzymes; it also known as catalytic RNA, ribozymes are found in the ribosome for protein formation and play a role in other vital mechanisms such as RNA splicing, transfer RNA biosynthesis, and viral replication. Discovery of catalytic RNA contributed to the hypothesis of prebiotic RNA world i.e. how life may have originated from an “RNA World” inhabited by self-replicating ribozymes. The ribosome is indeed a ribozyme underlines the relevance of RNA catalysis in today’s protein-dominated world.
The recent discoveries of RNA interference and micro-RNA associated mechanisms of gene regulation further emphasize the central importance of RNA to understanding gene regulation and leads to design new RNA-based technologies for gene manipulation and silencing.
The discovery that riboswitches and in some cases ribozymes, including a variant of the hammerhead ribozyme are also involved in regulating gene expression explains how intimately RNA structure, function, and catalysis are involved in many aspects of biological control.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
2. Definition
History of Ribozyme discovery
Characteristics of Ribozyme
Structure and mechanism of Ribozyme
Types of Ribozymes
Applications
3. Ribozymes (ribonucleic acid enzymes)
are RNA molecules that are capable of catalyzing
specific biochemical reactions, similar to the action of
protein enzymes.
Discovery revealed that RNA contributed to the ‘RNA
world hypothesis’
major role
a. Hydrolysis of phosphodiester bonds
b. Formation of bonds
c. Catalyze amino transferase activity of the
ribosome
4. • 1967 - Carl Woese, Francis Crick, and Leslie Orgel suggested
for the first time that RNA could act as a catalyst.
• 1970, Tomas R.Cech discovered the auto-splicing mechanism
of RNA molecule in Tetrahymena thermophila
• 1980s-T.R. Cech discovered catalytic RNAs
• 1982, Kelly Kruger coined the term ‘Ribozyme’ for these
catalytic RNA and published in “Cell”.
• mid-1980s Sidney Altman unraveled RNase P and its catalytic
role at University of Yale.
• 1989, T.R. Cech and S. Altman shared the Nobel Prize in
chemistry for their contributions in unraveling the catalytic
properties of RNA.
• 2001 "B6.61" could add up to 20 bases to a primer template
5. Contrary to central dogma
associated with metal ions
Uses RNA as its substrate
cleave other RNA molecules which
contained the NUX pattern of nucleotides
Present in every living organism
follows Michael-Menten kinetics
6. diverse structures and mechanisms using the
four nitrogen base choices other than the
diverse amino acids for protein structure
Image showing diversity of ribozyme structure
(Leadzyme, hammer head, twister ribozymes)
7. • Capable of cleaving mRNA molecules in a sequence specific,
catalytic manner.
• They contain sequences for selective ligation, cleavage reaction
with target mRNAs.
• By modifying substrate recognising sequences , ribozyme can be
specifically tailored for the supression of particular geners
8.
9. • involved in the
processing of
mRNA, tRNA &
rRNA.
• Splicing requires a
guanine residue
cofactor
• Self splicing by
trans esterification
10.
11. known as true RNAzyme
A ribonucleoprotein, discovered around 40
years ago
Mechanism of clevage is hydrolysis
12. Tiny 30 nucleotide autocatalytic RNA
It plays a role in reversible cleavage and joining
reactions at very specific site within RNA.
Hammerhead ribozymes RNAs were discovered initially
in satellite RNAs and viroids (plant viruses.
13. hepatitis delta virus (HDV) ribozyme
85 nucleotide long, non coding
plays role in viral replication. It is the only known
ribozyme required for the viability of a human
pathogen.
VS or Varkud satellite ribozyme is the largest
known natural nucleolytic RNA
satellite RNA is found in mitochondria of some
fungal strains like Neurospora
14. small ribozymes found
in RNA satellites of
plant viruses.
It assists in the
cleavage & ligation of
products of replication
to form circular and
linear satellite RNAs.
15.
16. Leadzyme- natural counterparts are in 5SrRNA.
Ligase ribozyme- catalyse the assembly of RNA
fragments to form its polymer
Allosteric ribozyme- act as molecular switches
regulatory segment of a messenger RNA molecule that
binds a small molecule, resulting in a change in
production of the proteins encoded by the mRNA
role in replication as well as in biological catalysis.
suggeststhat RNA might be the ancestor of the very first living form. The RNA due to its catalytic nature cancleave / ligate
RNA &performs other biochemical reactions like peptide bond synthesis.
in 24 hours.
(where N stands for any nucleotide, U for uracil, and X for adenine, uracil, or cytosine)
present in the organelles of eukaryotes (nucleus, mitochondria and chloroplasts),
amphibians, prokaryotes, bacteriophages, viroids and in satellite viruses that infect plants
tertiary structure of the ribozyme–substrate complex has been examined using a variety of
biochemical, biophysical, genetic, and computational methods.
By combining techniques like NMR spectroscopy, X-ray crystallography,
(FRET) fluorescence resonance energy transfer revealed the structure of the active site.
It was found to be comprised of multiple conserved functional groups
small RNAs of 50–150 nucleotides that perform site-specific self-cleavage
larger, more structurally complex ribozymes several hundred nucleotides in length
Found in bacteria , lower eukaryotes, plants
The secondary structure comprised of 9 paired regions (p1-p9)
known as true RNAzyme as it process 5’ Leader sequences of t-RNA i.e. CCA
This is also a metalloribozyme.
The hammerhead ribozyme has been well studied as a model system for
unraveling the structure and function of RNAs for therapeutic purposes
was named for its resemblance of the early secondary structure diagrams to a hammerhead
BUT ITS TERTIARY STRUCTURE IS MORE LIKE y SHAPED.
without any available structural data and found as embedded in VS RNA.
Even though these are similar to hammer head ribozyme, these do not require a metal cofactor for the reaction.
satellite RNA of - tobacco ringspot virus(sTRSV), chicory yellow mottle virus (sCYMV),arabis
mosaic virus (sARMV)
Peptidyl transferase is an aminoacyl transferase which is associated with the formation of peptide bonds between adjacent amino acids during the
translation process.
It is also the primary enzymatic function of the ribosome.
Peptidyl transferase activity is only mediated by ribosomal RNA (rRNA) has been well proven by site directed mutational
studies.
