2oug
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(New page: 200px<br /><applet load="2oug" size="450" color="white" frame="true" align="right" spinBox="true" caption="2oug, resolution 2.1Å" /> '''Crystal structure of ...)
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Revision as of 11:11, 21 November 2007
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Crystal structure of the RfaH transcription factor at 2.1A resolution
Overview
RfaH, a paralog of the general transcription factor NusG, is recruited to, elongating RNA polymerase at specific regulatory sites. The X-ray, structure of Escherichia coli RfaH reported here reveals two domains. The, N-terminal domain displays high similarity to that of NusG. In contrast, the alpha-helical coiled-coil C domain, while retaining sequence, similarity, is strikingly different from the beta barrel of NusG. To our, knowledge, such an all-beta to all-alpha transition of the entire domain, is the most extreme example of protein fold evolution known to date. Both, N domains possess a vast hydrophobic cavity that is buried by the C domain, in RfaH but is exposed in NusG. We propose that this cavity constitutes, the RNA polymerase-binding site, which becomes unmasked in RfaH only upon, sequence-specific binding to the nontemplate DNA strand that triggers, domain dissociation. Finally, we argue that RfaH binds to the beta', subunit coiled coil, the major target site for the initiation sigma, factors.
About this Structure
2OUG is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Structural basis for converting a general transcription factor into an operon-specific virulence regulator., Belogurov GA, Vassylyeva MN, Svetlov V, Klyuyev S, Grishin NV, Vassylyev DG, Artsimovitch I, Mol Cell. 2007 Apr 13;26(1):117-29. PMID:17434131
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