1mx0
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(New page: 200px<br /><applet load="1mx0" size="450" color="white" frame="true" align="right" spinBox="true" caption="1mx0, resolution 2.300Å" /> '''Structure of topois...)
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Revision as of 19:39, 20 November 2007
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Structure of topoisomerase subunit
Overview
Type IIA and type IIB topoisomerases each possess the ability to pass one, DNA duplex through another in an ATP-dependent manner. The role of ATP in, the strand passage reaction is poorly understood, particularly for the, type IIB (topoisomerase VI) family. We have solved the structure of the, ATP-binding subunit of topoisomerase VI (topoVI-B) in two states: an, unliganded monomer and a nucleotide-bound dimer. We find that topoVI-B is, highly structurally homologous to the entire 40-43 kDa ATPase region of, type IIA topoisomerases and MutL proteins. Nucleotide binding to topoVI-B, leads to dimerization of the protein and causes dramatic conformational, changes within each protomer. Our data demonstrate that type IIA and type, IIB topoisomerases have descended from a common ancestor and reveal how, ATP turnover generates structural signals in the reactions of both type II, topoisomerase families. When combined with the structure of the A subunit, to create a picture of the intact topoisomerase VI holoenzyme, the, ATP-driven motions of topoVI-B reveal a simple mechanism for strand, passage by the type IIB topoisomerases.
About this Structure
1MX0 is a Single protein structure of sequence from Sulfolobus shibatae with MG, NA and ANP as ligands. Active as DNA topoisomerase (ATP-hydrolyzing), with EC number 5.99.1.3 Full crystallographic information is available from OCA.
Reference
Structure of the topoisomerase VI-B subunit: implications for type II topoisomerase mechanism and evolution., Corbett KD, Berger JM, EMBO J. 2003 Jan 2;22(1):151-63. PMID:12505993
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