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X-RAY STRUCTURE OF GLYOXALASE II FROM ARABIDOPSIS THALIANA GENE AT2G31350X-RAY STRUCTURE OF GLYOXALASE II FROM ARABIDOPSIS THALIANA GENE AT2G31350
Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedGlyoxalase 2 is a beta-lactamase fold-containing enzyme that appears to be involved with cellular chemical detoxification. Although the cytoplasmic isozyme has been characterized from several organisms, essentially nothing is known about the mitochondrial proteins. As a first step in understanding the structure and function of mitochondrial glyoxalase 2 enzymes, a mitochondrial isozyme (GLX2-5) from Arabidopsis thaliana was cloned, overexpressed, purified, and characterized using metal analyses, EPR and (1)H NMR spectroscopies, and x-ray crystallography. The recombinant enzyme was shown to bind 1.04 +/- 0.15 eq of iron and 1.31 +/- 0.05 eq of Zn(II) and to exhibit k(cat) and K(m) values of 129 +/- 10 s(-1) and 391 +/- 48 microm, respectively, when using S-d-lactoylglutathione as the substrate. EPR spectra revealed that recombinant GLX2-5 contains multiple metal centers, including a predominant Fe(III)Z-n(II) center and an anti-ferromagnetically coupled Fe(III)Fe(II) center. Unlike cytosolic glyoxalase 2 from A. thaliana, GLX2-5 does not appear to specifically bind manganese. (1)H NMR spectra revealed the presence of at least eight paramagnetically shifted resonances that arise from protons in close proximity to a Fe(III)Fe(II) center. Five of these resonances arose from solvent-exchangeable protons, and four of these have been assigned to NH protons on metal-bound histidines. A 1.74-A resolution crystal structure of the enzyme revealed that although GLX2-5 shares a number of structural features with human GLX2, several important differences exist. These data demonstrate that mitochondrial glyoxalase 2 can accommodate a number of different metal centers and that the predominant metal center is Fe(III)Zn(II). Structural studies on a mitochondrial glyoxalase II.,Marasinghe GP, Sander IM, Bennett B, Periyannan G, Yang KW, Makaroff CA, Crowder MW J Biol Chem. 2005 Dec 9;280(49):40668-75. Epub 2005 Oct 14. PMID:16227621[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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