title: The crystal structure of Toxoplasma gondii nucleoside triphosphate diphosphohydrolase 1 represents a conformational intermediate in the reductive activation mechanism of the tetrameric enzyme.
abstract: Toxoplasma gondii nucleoside triphosphate diphosphohydrolase (NTPDase) 1 was crystallized in an intermediate tetrameric conformation. The crystal structure is similar to that of T. gondii NTPDase3 and represents an inactive conformation as the activating disulfide bridge is not reduced and the active site cleft between the two domains of each monomer is open. However, the arrangement of the monomers within the tetramer differs from that of the inactive form of NTPDase3 and may represent an intermediate conformation on the path of the closure motion of the tetramer induced upon activation.
authors.affiliation: Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Center for Biotechnology and Biomedicine, University of Leipzig, 04103 Leipzig, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Krug
authors.forename: Robert
authors.initials: R
authors.lastname: Totzauer
authors.forename: Norbert
authors.initials: N
authors.lastname: Sträter
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D000595:Amino Acid Sequence; D015703:Antigens, CD / Q000737:chemistry*; D001081:Apyrase / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D009711:Nucleotides / Q000737:chemistry; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011755:Pyrophosphatases / Q000737:chemistry*; D014122:Toxoplasma / Q000201:enzymology*
chemical_list: D015703:Antigens, CD; D009711:Nucleotides; D000255:Adenosine Triphosphate; D011755:Pyrophosphatases; C439652:nucleoside-triphosphate diphosphohydrolase 3; D001081:Apyrase; C067869:CD39 antigen