Description | Martin Buck is distinguished for his pioneering contributions to our understanding of molecular mechanisms of transcription initiation in bacteria. He was one of the first to identify enhancer-like elements in prokaryotes and he has extensively characterised a unique RNA polymerase sigma factor that is the taget for activation by bacterial enhancer binding proteins. His outstanding and innovative work has elucidated a new paradigm for transcriptional control in which the DNA melting steps rather than promoter occupancy steps are subject to regulation. He has established that nucleotide hydrolysis by the activator drives conformational changes in the sigma factor, which trigger the conversion of a transcriptionally silent RNA polymerase to a form that locally melts promoter DNA. By trapping the activator and sigma factor in a stable transition-state complex, he has identified an interaction surface on the activator that is required for coupling ATP hydrolysis to the remodelling of the RNA polymerase-promoter complex. |