Bacterial enhancer-binding proteins: unlocking sigma54-dependent gene transcription.

Centre for Structural Biology, Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK.
Current Opinion in Structural Biology (Impact Factor: 8.75). 03/2007; 17(1):110-6. DOI: 10.1016/
Source: PubMed

ABSTRACT Bacterial transcription relies on the binding of dissociable sigma (sigma) factors to RNA polymerase (RNAP) for promoter specificity. The major variant sigma factor (sigma54) forms a stable closed complex with RNAP bound to DNA that rarely spontaneously isomerises to an open complex. ATP hydrolysis by bacterial enhancer-binding proteins is used to remodel the RNAP-sigma54-DNA closed complex. Recently, a wealth of structural information on bacterial enhancer-binding proteins has enabled unprecedented insights into their mechanism. These data provide a structural basis for nucleotide binding and hydrolysis, oligomerisation and the conversion of ATPase activity into remodelling events within the RNAP-sigma54 closed complex, and represent advances towards a complete understanding of the sigma54-dependent transcription activation mechanism.

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