title: Nested cooperativity and salt dependence of the ATPase activity of the archaeal chaperonin Mm-cpn.
abstract: The properties of the ATPase activity of the type II chaperonin from Methanococcus maripaludis (Mm-cpn) were examined. Mm-cpn can hydrolyze not only ATP, but also CTP, UTP, and GTP, albeit with different effectiveness. The ATPase activity is dependent on magnesium and potassium ions, and is effectively inhibited by sodium ions. Maximal rates of ATP hydrolysis are achieved at 600 mM potassium. Initial rates of ATP hydrolysis by Mm-cpn were determined at various ATP concentrations, revealing for the first time the presence of both positive intra-ring and negative inter-ring cooperativity in the archaeal chaperonin.
authors.affiliation: Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Box G-J2, Providence, RI 02912, USA.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Kusmierczyk
authors.forename: Jörg
authors.initials: J
authors.lastname: Martin
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D019843:Archaeal Proteins / Q000378:metabolism*; D018833:Chaperonins / Q000378:metabolism*; D003570:Cytidine Triphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D017017:Methanococcus / Q000378:metabolism*; D009994:Osmolar Concentration; D012964:Sodium / Q000494:pharmacology*; D013379:Substrate Specificity; D014544:Uridine Triphosphate / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D003570:Cytidine Triphosphate; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D012964:Sodium; D000251:Adenosine Triphosphatases; D018833:Chaperonins; D014544:Uridine Triphosphate