PMID: 23389035

Authors:

Murakami KS

Title:

X-ray crystal structure of Escherichia coli RNA polymerase sigma70 holoenzyme.

Journal:

J Biol Chem. 2013 Mar 29;288(13):9126-34. doi: 10.1074/jbc.M112.430900. Epub 2013, Feb 6.

Abstract:

Escherichia coli RNA polymerase (RNAP) is the most studied bacterial RNAP and has been used as the model RNAP for screening and evaluating potential RNAP-targeting antibiotics. However, the x-ray crystal structure of E. coli RNAP has been limited to individual domains. Here, I report the x-ray structure of the E. coli RNAP sigma(70) holoenzyme, which shows sigma region 1.1 (sigma1.1) and the alpha subunit C-terminal domain for the first time in the context of an intact RNAP. sigma1.1 is positioned at the RNAP DNA-binding channel and completely blocks DNA entry to the RNAP active site. The structure reveals that sigma1.1 contains a basic patch on its surface, which may play an important role in DNA interaction to facilitate open promoter complex formation. The alpha subunit C-terminal domain is positioned next to sigma domain 4 with a fully stretched linker between the N- and C-terminal domains. E. coli RNAP crystals can be prepared from a convenient overexpression system, allowing further structural studies of bacterial RNAP mutants, including functionally deficient and antibiotic-resistant RNAPs.