Genetic mechanics
Everything — from noxious chemicals found in cigarette smoke or car exhaust, to ultraviolet radiation from the sun, to even something as benign as oxygen — is working overtime to damage DNA. Fortunately, all living things have a defense: an intra-cellular mechanic that patrols DNA, searching for errors and repairing them, thousands of times a day. Using X-ray crystallography, Harvard scientists produced 3-D images of the protein machinery that detects damaged parts of the genome in bacteria, thus enabling them to be repaired. The Harvard group used the images they obtained to gain a new understanding of how the DNA repair process works. As reported in the online version of Nature Structural & Molecular Biology on Feb. 5, the images reveal that the proteins can actually alter their shape. Researchers believe that the alteration is part of a process best described as a genetic “pat-down,” or a way for the mechanism to...