from the complex-molecular-machines dept.
A collaborative team from the Howard Hughes Medical Institute (HHMI) and Memorial Sloan-Kettering Cancer Center have produced the first detailed images of a protein that performs the crucial task of detecting and repairing broken strands of DNA. The images show that the protein is constructed to cradle DNA while the DNA is repaired and rejoined with great precision. A brief report appears on the HHMI website, and a research paper appeared in the 9 August 2001 issue of Nature.
The work reveals that the protein complex forms a ring that encircles and ìcradlesî the end of the strand of DNA. The scientists speculate that protein complexes on two broken ends of a DNA strand link to one another to hold the two ends in position for joining the DNA back together. They also found that the repair protein does not bind with the DNA bases, but rather grasps the sugar backbone of the DNA strand ó meaning that the protein does not ìcareî about the sequence of the DNA that it binds. The scientists also have evidence that proteins hold the DNA in precise alignment to allow re-joining by repair enzymes.