2ahq
From Proteopedia
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Solution Structure of the C-terminal RpoN Domain of Sigma-54 from Aquifex aeolicus
Overview
The "sigma" subunit of prokaryotic RNA polymerase allows gene-specific, transcription initiation. Two sigma families have been identified, sigma70, and sigma54, which use distinct mechanisms to initiate transcription and, share no detectable sequence homology. Although the sigma70-type factors, have been well characterized structurally by x-ray crystallography, no, high resolution structural information is available for the sigma54-type, factors. Here we present the NMR-derived structure of the C-terminal, domain of sigma54 from Aquifex aeolicus. This domain (Thr-323 to Gly-389), which contains the highly conserved RpoN box sequence, consists of a, poorly structured N-terminal tail followed by a three-helix bundle, which, is surprisingly similar to domains of the sigma70-type proteins. Residues, of the RpoN box, which have previously been shown to be critical for DNA, binding, form the second helix of an unpredicted helix-turn-helix motif., The homology of this structure with other DNA-binding proteins, combined, with previous biochemical data, suggests how the C-terminal domain of, sigma54 binds to DNA.
About this Structure
2AHQ is a Single protein structure of sequence from Aquifex aeolicus. Full crystallographic information is available from OCA.
Reference
The C-terminal RpoN domain of sigma54 forms an unpredicted helix-turn-helix motif similar to domains of sigma70., Doucleff M, Malak LT, Pelton JG, Wemmer DE, J Biol Chem. 2005 Dec 16;280(50):41530-6. Epub 2005 Oct 6. PMID:16210314
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