1z5a
Topoisomerase VI-B, ADP-bound dimer form
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 PubMedGHL proteins are functionally diverse enzymes defined by the presence of a conserved ATPase domain that self-associates to trap substrate upon nucleotide binding. The structural states adopted by these enzymes during nucleotide hydrolysis and product release, and their consequences for enzyme catalysis, have remained unclear. Here, we have determined a complete structural map of the ATP turnover cycle for topoVI-B, the ATPase subunit of the archaeal GHL enzyme topoisomerase VI. With this ensemble of structures, we show that significant conformational changes in the subunit occur first upon ATP binding, and subsequently upon release of hydrolyzed P(i). Together, these data provide a structural framework for understanding the role of ATP hydrolysis in the type II topoisomerase reaction. Our results also suggest that the GHL ATPase module is a molecular switch in which ATP hydrolysis serves as a prerequisite but not a driving force for substrate-dependent structural transitions in the enzyme. Structural dissection of ATP turnover in the prototypical GHL ATPase TopoVI.,Corbett KD, Berger JM Structure. 2005 Jun;13(6):873-82. PMID:15939019[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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