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Two postdoctoral positions are available immediately in the lab of Carrie Wilmot (University of Minnesota, Minneapolis, USA) to structurally characterize the catalytic mechanisms of two heme enzymes, chlorite dismutase and MauG. Chlorite dismutase (Cld) is a b-type mono-heme enzyme capable of rapidly and selectively decomposing chlorite to Cl¯ and O2. The ability of Cld to promote O2 formation from chlorite (ClO2¯) is unusual, making Cld the only known enzymatic system outside of photosystem II that has evolved to efficiently catalyze O-O bond formation. We have recently solved the X-ray crystal structure of Dechloromonas aromatica Cld (Goblirsch et al (2010) J. Biol. Inorg. Chem. 15: 879-88). Cld was first isolated and characterized from perchlorate respiring organisms, where the enzyme is involved in the breakdown of perchlorate, a serious fresh water pollutant that leads to thyroid dysfunction. It is now clear that gene sequences annotated as clds are extremely widespread in ~500 highly taxonomically diverse organisms, the overwhelming majority of which do not respire perchlorate. In addition to studying the mechanism of Cld catalyzed chlorite dismutation, we are interested in the function of these uncharacterized homologs. The project will involve X-ray crystallography, single crystal spectroscopy (UV-visible, X-ray absorption) and freeze trapping of catalytic intermediates in the crystal for structural studies. MauG is a di-heme enzyme responsible for the posttranslational modification of two tryptophan residues to form the tryptophan tryptophylquinone cofactor (TTQ) of methylamine dehydrogenase (MADH). MauG converts preMADH, the precursor protein containing monohydroxylated-βTrp57, to fully functional MADH by catalyzing the insertion of a second oxygen atom into the indole ring and covalently linking βTrp57 to βTrp108. We have recently solved the X-ray crystal structure of MauG complexed with preMADH (Jensen et al. (2010) Science 327: 1392-4). The c-type heme irons and the nascent TTQ site are separated by long distances over which electron transfer must occur to achieve catalysis. In addition one of the hemes has an atypical His-Tyr axial ligation. The crystalline protein complex is catalytically competent, as on addition of hydrogen peroxide MauG-dependent TTQ synthesis occurs. The project will involve X-ray crystallography, mass spectrometry, single crystal spectroscopy (UV-visible, Raman, X-ray absorption) and freeze trapping catalytic intermediates in the crystal. The positions are available immediately, with a highly competitive salary commensurate with experience. Applicants must have a recent Ph.D. in biochemistry, chemistry, molecular biology or a closely related field. Applicants should have demonstrated expertise in macromolecular crystallography. Candidates should submit a cover letter that includes a brief statement of previous research experience and interests, along with a detailed CV and the names of 3 references. Review of applications will start immediately and continue until the positions are filled. For additional information or to make an application contact: Dr. Carrie Wilmot,Associate Professor and Director of the Kahlert Structural Biology Laboratory, University of Minnesota, Department of Biochemistry, Molecular Biology & Biophysics, 6-155 Jackson Hall, 321 Church St SE, Minneapolis, MN 55455-0215, USA. E-mail: wilmo004@umn.edu Tel: +1-612-624-2406 WWW: http://www.cbs.umn.edu/BMBB/html/Faculty/Wilmot.C.M.html --
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