1xs9

From Proteopedia

Revision as of 04:11, 21 November 2007

A MODEL OF THE TERNARY COMPLEX FORMED BETWEEN MARA, THE ALPHA-CTD OF RNA POLYMERASE AND DNA

Overview

The transcriptional activator, MarA, interacts with RNA polymerase (RNAP), to activate promoters of the mar regulon. Here, we identify the, interacting surfaces of MarA and of the carboxy-terminal domain of the, alpha subunit of RNAP (alpha-CTD) by NMR-based chemical shift mapping., Spectral changes were monitored for a MarA-DNA complex upon titration with, alpha-CTD, and for alpha-CTD upon titration with MarA-DNA. The mapping, results were confirmed by mutational studies and retention chromatography., A model of the ternary complex shows that alpha-CTD uses a '265-like, determinant' to contact MarA at a surface distant from the DNA. This is, unlike the interaction of alpha-CTD with the CRP or Fis activators where, the '265 determinant' contacts DNA while another surface of the same, alpha-CTD molecule contacts the activator. These results reveal a new, versatility for alpha-CTD in transcriptional activation.

About this Structure

1XS9 is a Protein complex structure of sequences from Escherichia coli. This structure superseeds the now removed PDB entry 1TI9. Active as DNA-directed RNA polymerase, with EC number 2.7.7.6 Full crystallographic information is available from OCA.

Reference

Versatility of the carboxy-terminal domain of the alpha subunit of RNA polymerase in transcriptional activation: use of the DNA contact site as a protein contact site for MarA., Dangi B, Gronenborn AM, Rosner JL, Martin RG, Mol Microbiol. 2004 Oct;54(1):45-59. PMID:15458404

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