CHAPEL HILL - Researchers at the University of North Carolina at Chapel Hill have discovered part of one of the processes by which the body repairs the genetic material known as DNA inside cells.
Using a combination of sophisticated genetic and biochemical techniques, they have solved a lingering debate among scientists by showing that a protein called DNA helicase II can act individually and need not be coupled with one or more identical proteins while making repairs.
"If you are going to fix a car that's broken, it's useful to know how it's supposed to work in the first place and then to understand how it's broken," said Dr. Steven W. Matson, professor and associate chair of biology at UNC-CH. "That's what this work does. It brings us a little closer to understanding how to correct biological processes when they are defective in cells."
A report on the findings appears in the April 30 issue of the Journal of Biological Chemistry. Besides Matson, authors are Leah E. Mechanic, a UNC-CH biochemistry graduate student, and Dr. Mark C. Hall, postdoctoral fellow at the National Institute of Environmental Health Sciences in Research Triangle Park.
To understand the new work, Matson said it's important to remember that the DNA molecule consists of long, paired and twisted strands of smaller subunits that repeat in various combinations and form genes. Models of DNA can look like toy railroad tracks that spiral along their entire length.
"Discovered about 20 years ago, DNA helicases, which are enzymes, separate one strand of DNA from the other temporarily, a process that is required before the DNA can be repaired or replicated," he said. "We now believe that they bind to one of the two strands and move along it, something like an inchworm moving along a tree branch."
For the past four or five years, scientists have studied and debated
whether helicases act with one or more partners. Working with E. c
Contact: David Williamson
University of North Carolina at Chapel Hill