Outrunning the Bear

Survival of the fittest describes a new method for screening dynamic combinatorial libraries. A mixture of dipeptides is tested for binding to a target protein, and the weaker binding compounds are destroyed by pronase. The released components are then recoupled to regenerate the library. By repeating this cycle of selection, destruction, and regeneration, a small binding preference eventually results in a large enrichment of the tightest binding compound. Photo credit Douglas Jager (http://www.mindspring.com/~bjager/akpix2.html).