all Eugene I. Shakhnovich stories

‘Speed limit’ found on rate of evolution

jake — Mon, 22 Oct 2007 13:10:24 -0400

Harvard University scientists have identified a virtual “speed limit” on the rate of molecular evolution in organisms, and the magic number appears to be six mutations per genome per generation — a rate of change beyond which species run the strong risk of extinction as their genomes lose stability.

By modeling the stability of proteins required for an organism’s survival, Eugene Shakhnovich and his colleagues have discovered this essential thermodynamic limit on a species’ rate of evolution. Their discovery, published this week in the Proceedings of the National Academy of Sciences, draws a crucial connection between the physical properties of genetic material and the survival fitness of an entire organism.

Comprehensive model first to map protein folding at atomic level

Thu, 12 Jul 2007 09:53:08 -0400

Scientists at Harvard University have developed a computer model that, for the first time, can fully map and predict how small proteins fold into three-dimensional, biologically active shapes. The work could help researchers better understand the abnormal protein aggregation underlying some devastating diseases, as well as how natural proteins evolved and how proteins recognize correct biochemical partners within living cells.

The technique, which can track protein folding for some 10 microseconds - about as long as some proteins take to assume their biologically stable configuration, and at least a thousand times longer than previous methods - is described this week in the Proceedings of the National Academy of Sciences (PNAS).