RNA polymerase motions during promoter melting

• DOI: 10.1126/science.aam7858
• Publication Date: 2017-05-25T21:40:11Z
• Authors: Andrey Feklistov; Brian Bae; Jesse Hauver; Agnieszka Lass-Na...; Markus Kalesse; Florian Glaus; Karl-Heinz Altmann; Tomasz Heyduk; Robert Landick; Seth A. Darst
• Keywords: RNA polymerase II

All cellular RNA polymerases (RNAPs), from those of bacteria to man, possess a clamp that can open and close, it has been assumed the RNAP separates promoter DNA strands then closes establish tight grip on template. Here, we resolve successive motions initiating bacterial by studying real-time signatures fluorescent reporters placed in presence ligands locking distinct conformations. We report evidence for an unexpected obligatory step early initiation involving transient closure as prerequisite melting. also present 2.6-angstrom crystal structure late-initiation intermediate harboring rotationally unconstrained downstream duplex within active site cleft. Our findings explain how thermal control search drive melting absence external energy sources.