HOME >> BIOLOGY >> NEWS
How DNA copying enzyme 'stops the presses' for repair synthesizing enzyme

DURHAM, N.C. -- Biochemists have performed detailed structural studies that reveal for the first time how an enzyme key to DNA replication stalls when an error occurs, to allow it to be corrected. Without such instantaneous braking, such mistakes in DNA replication would wreak havoc on DNA replication, killing the cell.

To their surprise, the scientists observed how the enzyme, DNA polymerase, retains a "short-term memory" of mismatches, in some cases halting itself past the point of the mismatch, so that the repair machinery can go to work. They also found that the mismatch structures differed dramatically from those deduced from previous indirect biochemical studies.

In an article in the March 19, 2004, issue of the journal Cell, Duke University Medical Center biochemists Sean Johnson and Lorena Beese, Ph.D., described how they had conducted detailed structural analyses of DNA polymerase as it encountered each of the 12 possible kinds of mismatches possible in DNA replication.

In such replication, the polymerase sequentially attaches DNA units called bases along a single-stranded template DNA. The result is like constructing one rail of a spiral staircase, using the other rail as a guide; and the polymerase "translocates" the template strand through its active site like a thread through the eye of a needle.

In this replication process, the polymerase normally guides the template strand and assembles the complementary, growing "primer" strand by pairing each base with the correct counterpart -- always pairing adenine with thymine and cytosine with guanine.

When mismatches occur, the polymerase must instantly halt itself, triggering the mismatch repair machinery to launch into action, before replication can continue. This stalling is thought to occur because the polymerase-DNA structure is distorted by the mismatched bases, causing it to shut down.

The problem, said Beese, who is an associate professor of biochemistr
'"/>

Contact: Dennis Meredith
dennis.meredith@duke.edu
919-681-8054
Duke University Medical Center
30-Mar-2004


Page: 1 2 3

Related biology news :

1. Two separate controls regulate chromosome copying in yeast
2. Scientists decipher "fail-safe" system that limits gene copying in cells
3. Anthrax enzyme images reveal secrets of antibiotic resistance, suggest new drug design
4. First glimpse of DNA binding to viral enzyme
5. Two enzymes key to calorie-burning, Brown research shows
6. Argonne scientists determine structure of staph, anthrax enzyme
7. Brain serotonin enzyme finding might explain psychiatric disorders
8. Study finds plant enzyme function changes with location in cell
9. Basic RNA enzyme research promises single-molecule biosensors
10. Molecule that blocks key bacterial enzyme may lead to new antibiotics
11. Study finds first evidence COX-2 enzymes can regulate DNA damage

Post Your Comments:
(Date:10/14/2014)... the house fly genome for the first time, revealing ... insect that thrives in pathogen-rich dung piles and garbage ... journal Genome Biology , will increase understanding of ... quickly adapt to resist insecticides, which could lead to ... carry and transmit more than 100 human and animal ...
(Date:10/14/2014)... research team has discovered a new kind of stem cell ... that lines liver blood vessels, according to a study published ... existence of such a cell type contradicts current theory on ... may hold clues to origins of, and future treatment for, ... single cell into a complex being made up of more ...
(Date:10/14/2014)... 14, 2014 – Scientists from The Scripps Research Institute ... Institutes of Health (NIH) to lead an investigation of ... disease in Africa. The study aims to understand how ... die, while others survive the inflection. , "The ... mechanism of how Lassa fever virus causes disease and ...
Breaking Biology News(10 mins):House fly genome reveals expanded immune system 2Stem cell discovery challenges dogma on how fetus develops; holds insights for liver cancer and reg 2Stem cell discovery challenges dogma on how fetus develops; holds insights for liver cancer and reg 3Scripps Research Institute team receives $6.6 million to investigate deadly Lassa virus 2
(Date:10/20/2014)... BIOREM Inc. (TSXV: BRM) ("Biorem" or "the Company") today announced four ... million and provides a good start to Q4.  The orders are ... and one in the Middle East . ... said Peter Bruijns , President & CEO. "Total bidding activity ... they have been for any complete year since the company has ...
(Date:10/20/2014)... N.J. (PRWEB) October 20, 2014 ... the Sidney Kimmel Cancer Center at Thomas Jefferson ... , Through the Strategic Alliance Partnership program, ... OncLive will collaborate to raise awareness of the ... treatment, and other projects. Clinicians and other health ...
(Date:10/19/2014)... October 20, 2014 OCTOBER ... Meeting (ABIM). ABIM will take place ... information about ABIM 2014 is now available ... Delegates representing companies and organizations from all ... obtain information on the latest products and ...
(Date:10/19/2014)... The Asia-Pacific Speech Analytics market report ... with analysis and forecast of revenue. This market is ... $208 million by 2019, at a Compound Annual Growth ... Browse through the TOC of the Asia-Pacific Speech Analytics ... analysis provided. It also provides a glimpse of the ...
Breaking Biology Technology:Sidney Kimmel Cancer Center at Thomas Jefferson University Partners With OncLive 2Sidney Kimmel Cancer Center at Thomas Jefferson University Partners With OncLive 3The Asia-Pacific Speech Analytics market is estimated to reach $208 million by 2019 - New Report by MicroMarket Monitor 2The Asia-Pacific Speech Analytics market is estimated to reach $208 million by 2019 - New Report by MicroMarket Monitor 3The Asia-Pacific Speech Analytics market is estimated to reach $208 million by 2019 - New Report by MicroMarket Monitor 4
Cached News: