Motors, Switches and Contacts in a Replisome |
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| Air date: | Wednesday, April 18, 2007, 3:00:00 PM |
| Category: | Wednesday Afternoon Lectures |
| Runtime: | 75 minutes |
| NLM Title: | Motors, switches, and contacts in a replisome [electronic resource] / Charles C. Richardson. |
| Series: | NIH director's Wednesday afternoon lecture series |
| Author: | Richardson, Charles C. National Institutes of Health (U.S.) |
| Publisher: | [Bethesda, Md. : National Institutes of Health, 2007] |
| Other Title(s): | NIH director's Wednesday afternoon lecture series |
| Abstract: | (CIT): The assembly of proteins, the replisome, that replicates DNA is comprised of molecular motors, switches, and multiple protein-protein contacts that coordinate the movement of the replication fork. Although differing in complexity, the basic machinery of all replication systems is remarkably conserved throughout evolution. The economy of proteins found in the replication system of bacteriophage T7 has made possible the analysis of a replisome at the molecular level. Four proteins of known crystal structure are sufficient for the basis reactions: T7 DNA polymerase and its processivity factor (E. coli thioredoxin), T7 helicase-primase, and T7 ssDNA binding protein. A reconstituted replisome effects DNA synthesis in which leading and lagging strand synthesis are coordinated and processive. Nascent Okazaki fragments are found within a loop of lagging strand DNA. Single molecule techniques reveal the consequence of contacts between the polymerase and helicase-primase and suggest mechanisms for the recycling of the lagging strand DNA polymerase from a completed Okazaki fragment to a new RNA primer. The research in the laboratory of Charles C. Richardson focuses on the enzymology and molecular biology of DNA replication and recombination. After completing medical school and a one-year residency in medicine at Duke Hospital he joined the laboratory of Arthur Kornberg at Stanford Medical School as a research fellow. During this period he discovered exonuclease III of Escherichia coli and used it as a reagent to characterize DNA synthesis catalyzed by DNA polymerase I. Upon joining the faculty at Harvard Medical School the Richardson laboratory discovered T4 polynucleotide kinase, T4 DNA ligase, T7 DNA polymerase, helicase, and primase, and E. coli exonuclease VII and DNA polymerase II. His group has used these enzymes as reagents for end-group analysis of DNA, for the development of novel DNA sequencing reagents, and for the characterization of novel steps in replication. In recent years the Richardson laboratory has focused on the replication system of bacteriophage T7. The limited number of proteins has enabled the reconstitution of a functional replisome, a determination of the structures of functional complexes, and a visualization of active replisomes by single-molecule techniques. The Richardson laboratory has maintained collaborative efforts during this period with Jack Griffith, Tom Ellenberger, and Antoine van Oijen. The NIH Director's Wednesday Afternoon Lecture Series includes weekly scientific talks by some of the top researchers in the biomedical sciences worldwide. |
| Subjects: | DNA Primase--genetics DNA Replication--genetics |
| Publication Types: | Government Publications Lectures |
| Download: | Download
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| NLM Classification: | QU 475 |
| NLM ID: | 101306076 |
| CIT File ID: | 13773 |
| CIT Live ID: | 5197 |
| Permanent link: | http://videocast.nih.gov/launch.asp?13773 |
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Enhanced Audio Podcast | 1:08:53 |
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Enhanced Video Podcast | 1:08:53 | |