title: Structural dissection of ATP turnover in the prototypical GHL ATPase TopoVI.
abstract: GHL 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.
authors.affiliation: Department of Molecular and cellular biology, University of California, Berkeley, California 94720, USA.
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Corbett
authors.forename: James M
authors.initials: JM
authors.lastname: Berger
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D019843:Archaeal Proteins; D001665:Binding Sites; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004250:DNA Topoisomerases, Type II / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D006868:Hydrolysis; D008239:Lysine / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D010758:Phosphorus / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D019843:Archaeal Proteins; D021122:Protein Subunits; D014867:Water; D010758:Phosphorus; D000251:Adenosine Triphosphatases; C105141:DNA topoisomerase VI; D004250:DNA Topoisomerases, Type II; D008239:Lysine