1suu

From Proteopedia

Revision as of 00:34, 21 November 2007

Structure of DNA gyrase A C-terminal domain

Overview

DNA gyrase is unique among enzymes for its ability to actively introduce, negative supercoils into DNA. This function is mediated in part by the, C-terminal domain of its A subunit (GyrA CTD). Here, we report the crystal, structure of this approximately 35-kDa domain determined to 1.75-A, resolution. The GyrA CTD unexpectedly adopts an unusual fold, which we, term a beta-pinwheel, that is globally reminiscent of a beta-propeller but, is built of blades with a previously unobserved topology. A large, conserved basic patch on the outer edge of this domain suggests a likely, site for binding and bending DNA; fluorescence resonance energy, transfer-based assays show that the GyrA CTD is capable of bending DNA by, > or =180 degrees over a 40-bp region. Surprisingly, we find that the CTD, of the topoisomerase IV A subunit, which shares limited sequence homology, with the GyrA CTD, also bends DNA. Together, these data provide a physical, explanation for the ability of DNA gyrase to constrain a positive, superhelical DNA wrap, and also suggest that the particular substrate, preferences of topoisomerase IV might be dictated in part by the function, of this domain.

About this Structure

1SUU is a Single protein structure of sequence from Borrelia burgdorferi. Active as DNA topoisomerase (ATP-hydrolyzing), with EC number 5.99.1.3 Full crystallographic information is available from OCA.

Reference

The C-terminal domain of DNA gyrase A adopts a DNA-bending beta-pinwheel fold., Corbett KD, Shultzaberger RK, Berger JM, Proc Natl Acad Sci U S A. 2004 May 11;101(19):7293-8. Epub 2004 May 3. PMID:15123801

Page seeded by OCA on Wed Nov 21 02:41:29 2007