title: Effects of specific amino acid substitutions on activities of dinitrogenase reductase-activating glycohydrolase from Rhodospirillum rubrum.
abstract: Site-directed mutagenesis of the draG gene was used to generate altered forms of dinitrogenase reductase-activating glycohydrolase (DRAG) with D123A, H142L, H158N, D243G, and E279R substitutions. The amino acid residues H142 and E279 are not required either for the coordination to the metal center or for catalysis since the variants H142L and E279R retained both catalytic and electron paramagnetic resonance spectral properties similar to those of the wild-type enzyme. Since DRAG-H158N and DRAG-D243G variants lost their ability to bind Mn(II) and to catalyze the hydrolysis of the substrate, H158 and D243 residues could be involved in the coordination of the binuclear Mn(II) center in DRAG.
authors.affiliation: Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
authors.forename: B S
authors.initials: BS
authors.lastname: Antharavally
authors.forename: R R
authors.initials: RR
authors.lastname: Poyner
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: G P
authors.initials: GP
authors.lastname: Roberts
authors.forename: P W
authors.initials: PW
authors.lastname: Ludden
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases; D012247:Rhodospirillum rubrum / Q000201:enzymology* / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D006026:Glycoside Hydrolases; D009699:N-Glycosyl Hydrolases; C036091:ADP-ribosyl-(dinitrogen reductase) hydrolase