1l9z
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(New page: 200px<br /><applet load="1l9z" size="450" color="white" frame="true" align="right" spinBox="true" caption="1l9z, resolution 6.5Å" /> '''Thermus aquaticus RNA...)
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Revision as of 18:17, 20 November 2007
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Thermus aquaticus RNA Polymerase Holoenzyme/Fork-Junction Promoter DNA Complex at 6.5 A Resolution
Overview
The crystal structure of Thermus aquaticus RNA polymerase holoenzyme, (alpha2betabeta'omegasigmaA) complexed with a fork-junction promoter DNA, fragment has been determined by fitting high-resolution x-ray structures, of individual components into a 6.5-angstrom resolution map. The DNA lies, across one face of the holoenzyme, completely outside the RNA polymerase, active site channel. All sequence-specific contacts with core promoter, elements are mediated by the sigma subunit. A universally conserved, tryptophan is ideally positioned to stack on the exposed face of the base, pair at the upstream edge of the transcription bubble. Universally, conserved basic residues of the sigma subunit provide critical contacts, with the DNA phosphate backbone and play a role in directing the melted, DNA template strand into the RNA polymerase active site. The structure, explains how holoenzyme recognizes promoters containing variably spaced, -10 and -35 elements and provides the basis for models of the closed and, open promoter complexes.
About this Structure
1L9Z is a Protein complex structure of sequences from Thermus aquaticus with MG and ZN as ligands. Active as DNA-directed RNA polymerase, with EC number 2.7.7.6 Full crystallographic information is available from OCA.
Reference
Structural basis of transcription initiation: an RNA polymerase holoenzyme-DNA complex., Murakami KS, Masuda S, Campbell EA, Muzzin O, Darst SA, Science. 2002 May 17;296(5571):1285-90. PMID:12016307
Page seeded by OCA on Tue Nov 20 20:24:58 2007
