Study finds protein directing DNA repair

CHAMPAIGN, Ill., Oct. 22 (UPI) -- U.S. scientists say they've found the first protein that randomly moves along a single strand of DNA, selectively allowing other proteins access to the DNA.

Researchers from the University of Illinois and Washington University noted the double-helix of DNA unwinds into single strands for replication and other purposes. Scientists had assumed the single-stranded DNA binding protein SSB they studied attached to a site on the DNA and later detached.

But in a series of experiments, the researchers discovered SSB moves along single-stranded DNA, and its movement is independent of the sequence of nucleotides comprising the DNA.

They said they also found a protein involved in DNA repair in the bacterium E. coli grows along the DNA in response to the movement of SSB, and prevents the backward movement of the binding protein.

The researchers, led by Professor Taekjip Ha, posit SSB modulates the activity of many proteins that have a role in DNA repair, recombination and replication.

"SSB may be a master coordinator of all these important processes," said Ha.

The study is detailed in the journal Nature.