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Molecular biology


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Molecular biology

  1. 1. 'Cowcatcher' Enzyme Fixes Single-Strand DNA AND Key Step in Molecular 'Dance' That Duplicates DNA Deciphered  CARMEN SOFIA TORRES DAZA Medical Student III semester Medellín/UPB
  2. 2. DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. An important property of DNA is that it can replicate, or make copies of itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell. Before it can occur, the length of the DNA double helix about to be copied must be unwound. In addition, the two strands must be separated, much like the two sides of a zipper, by breaking the weak hydrogen bonds that link the paired bases. Once the DNA strands have been unwound, they must be held apart to expose the bases so that new nucleotide partners can hydrogen-bond to them. If in this important process is found an error , its necessary stop the replication for correct the implicated bases and then continue whit this.
  3. 3. 'Cowcatcher' Enzyme Fixes Single-Strand DNA “science daily, July 29 2013”   FIRST NEW
  4. 4. When a cell divides, this cell exposes its genome. Prior to cell division, this DNA splits into two single strands and these splits are so vulnerable to many assaults. This assaults can generates changes in the genetic information and if the assaults don´t correct will be generate mutations… this damage can produce cancers and other illness to the people. FIRST NEW
  5. 5. According with the authors, this investigation helps us to imagine the DNA separation during replication as a zipper. This zipper opens and expose it bases, and the problem is that the new strand is susceptible to damage and lead to breaking it. FIRST NEW
  6. 6. Was Founded!!! NEIL 1 : “The Cowcatcher” … In a in vitro experiments, scientists founded a enzyme called NEIL 1 . This enzyme actually rides in front of the replication process looking a single strand DNA damage. For this reason was called “ cowcatcher”. If the cowcatcher detect a damage the NEIL 1 binds to the damage site and "stop" the replication . literally it works of this way: “There is a regresses and the two strands come back together which allows repair of the damaged base in duplex DNA, replacing the damaged base with the appropriate normal base.“ for understanding this, the author of the article, Sankar Mitra, makes an analogy for the function of NEIL 1: he call it the cowcatcher by comparing it with the structure of a “locomotive on it front side” that is used to take off the animals or debris out of the road. “basically the cowcatcher is in front of the train of the replication to see if there is any damage in front of it” “if there is any damaged found, the train moves back, repairs it and then start to moving again” FIRST NEW
  7. 7. PERSONAL OPINION: this investigation is a good example for show as molecular biology is becomes today in the way to new goals and knowledge that help to improve the life quality of the people. FIRST NEW
  8. 8. Key Step in Molecular 'Dance' That Duplicates DNA Deciphered   “science daily, July 14 2013” SECOND NEW
  9. 9. This research, was published in the journal Nature Structural & Molecular Biology and give us information about the some key step-molecular through images showing how the enzyme that unwinds the DNA double helix gets drawn to and wrapped around its target. And, also the details and mechanism of DNA replication with important implications in current cáncer investigations. SECOND NEW
  10. 10. The "origin recognition complex" (ORC), identifies and binds to DNA- replication "start" sites, and it is a important factor in this is process because this protein also interacts with the enzyme that eventually unwinds the DNA double helix into two separate strands. There are a kind of missing link- what happens to this helicase. This helicase needs different protein components to generate a helicase loading complex. SECOND NEW
  11. 11. They purified and then remixed together pieces of the protein including the origin recognition complex, the replication initiator, the core of the helicase, and other components and embedded them in ice, took pictures with a cryo- electron microscope and reconstructe the 3-D structure in a computer. "The 3-D reconstruction gave their a snapshot of the elusive intermediate structure. This intermediate structure is a very important part of the molecular machinery that exist on fleeting timescales. This investigations about the helicasa have important implications, possibly pointing to new ways to fight cancer, because irregularities in DNA duplication and uncontrolled cell division are hallmarks of the disease. SECOND NEW
  12. 12. PERSONAL OPINION I think in a way this article keeps relation with the previous , because "stop" the cell replication when it detects any damage is very important to save the lives of many people with many types of cancers.
  13. 13. MEDICAL UTILITY The DNA is contained all the genetic information of a living being. The study of DNA is important in many subjects of the science but in medicine specially because we can know why some people are more predisposed than others to certain diseases or why some people respond better than others to the treatments used against some diseases. You can also learn what environmental factors influence people with a particular genetic heritage that make developing certain diseases and those same people in another environment does not develop. MEDICAL UTILITY
  14. 14. This whole set of genetic studies / genome will allow researchers to develop better treatments for some diseases and determine which factors should be avoided by individuals to prevent the development of some diseases. MEDICAL UTILITY
  15. 15. We know some genes are involved in certain hereditary diseases and today are conducting studies to discover exactly the site or sites in the genome that are involved in it, knowing the risk factor in the population and its mode of inheritance. Also used for human identification, for paternity, forensic identification which has been very useful in the judicial branch. MEDICAL UTILITY
  16. 16. And as we know the great utility of the DNA molecule, it is also clear the importance of today of repair damage to the genome level. In this way, doctors can improve and even slow the lives of their patients. MEDICAL UTILITY
  17. 17. BIBLIOGRAPHY ¨ Science daily , “ 'Cowcatcher' Enzyme Fixes Single-Strand DNA “ , published on July 29 2013, in the National Academy of Sciences, [ ] . ¨ Science daily, “Key Step in Molecular 'Dance' That Duplicates DNA Deciphered ” , published on July 14 2013, in the journal Nature Structural & Molecular Biology , [ ] .  
  18. 18. THANKS!!