The crystal structure of a homodimeric Pseudomonas glyoxalase I enzyme reveals asymmetric metallation commensurate with half-of-sites activity Academic Article uri icon


  • 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.


  • Bythell-Douglas, R
  • Suttisansanee, U
  • Flematti, GR
  • Challenor, M
  • Lee, M
  • Panjikar, S
  • Honek, JF
  • Bond, CS

publication date

  • 2015