1mx0
Structure of topoisomerase subunit
Structural highlights
FunctionTOP6B_SACSH Relaxes both positive and negative supercoils and exhibits a strong decatenase and unknotting activity; it cannot introduce DNA supercoils (PubMed:7961685). ATP is absolutely required for DNA cleavage; the nonhydrolyzable analog AMP-PNP generates nicked or linear products from a supercoiled dsDNA substrate. Generates staggered two-nucleotide long 5' overhangs. The enzyme is covalently attached transiently to the 5'-ends of the cleaved strands (PubMed:11485995).[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedType 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. 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[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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