title: The crystal structure of a homodimeric Pseudomonas glyoxalase I enzyme reveals asymmetric metallation commensurate with half-of-sites activity.
abstract: The Zn inactive class of glyoxalase I (Glo1) metalloenzymes are typically homodimeric with two metal-dependent active sites. While the two active sites share identical amino acid composition, this class of enzyme is optimally active with only one metal per homodimer. We have determined the X-ray crystal structure of GloA2, a Zn inactive Glo1 enzyme from Pseudomonas aeruginosa. The presented structures exhibit an unprecedented metal-binding arrangement consistent with half-of-sites activity: one active site contains a single activating Ni(2+) ion, whereas the other contains two inactivating Zn(2+) ions. Enzymological experiments prompted by the binuclear Zn(2+) site identified a novel catalytic property of GloA2. The enzyme can function as a Zn(2+) /Co(2+) -dependent hydrolase, in addition to its previously determined glyoxalase I activity. The presented findings demonstrate that GloA2 can accommodate two distinct metal-binding arrangements simultaneously, each of which catalyzes a different reaction.
authors.affiliation: School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Western Australia (Australia).
authors.forename: Rohan
authors.initials: R
authors.lastname: Bythell-Douglas
authors.forename: Uthaiwan
authors.initials: U
authors.lastname: Suttisansanee
authors.forename: Gavin R
authors.initials: GR
authors.lastname: Flematti
authors.forename: Michael
authors.initials: M
authors.lastname: Challenor
authors.forename: Mihwa
authors.initials: M
authors.lastname: Lee
authors.forename: Santosh
authors.initials: S
authors.lastname: Panjikar
authors.forename: John F
authors.initials: JF
authors.lastname: Honek
authors.forename: Charles S
authors.initials: CS
authors.lastname: Bond
mesh_terms: D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D007791:Lactoylglutathione Lyase / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D011487:Protein Conformation; D011552:Pseudomonas Infections / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D015032:Zinc / Q000737:chemistry / Q000378:metabolism
chemical_list: D007791:Lactoylglutathione Lyase; D015032:Zinc
keywords: crystal-structure determination; enzymes; metalloenzymes; proteins; zinc