1e5k
CRYSTAL STRUCTURE OF THE MOLYBDENUM COFACTOR BIOSYNTHESIS PROTEIN MOBA (PROTEIN FA) FROM ESCHERICHIA COLI AT NEAR ATOMIC RESOLUTION
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OverviewOverview
BACKGROUND: All mononuclear molybdoenzymes bind molybdenum in a complex, with an organic cofactor termed molybdopterin (MPT). In many bacteria, including Escherichia coli, molybdopterin can be further modified by, attachment of a GMP group to the terminal phosphate of molybdopterin to, form molybdopterin guanine dinucleotide (MGD). This modification reaction, is required for the functioning of many bacterial molybdoenzymes, including the nitrate reductases, dimethylsulfoxide (DMSO) and, trimethylamine-N-oxide (TMAO) reductases, and formate dehydrogenases. The, GMP attachment step is catalyzed by the cellular enzyme MobA. RESULTS: The, crystal structure of the 21.6 kDa E. coli MobA has been determined by MAD, phasing with selenomethionine-substituted protein and subsequently refined, at 1. 35 A resolution against native data. The structure consists of a, central, predominantly parallel beta sheet sandwiched between two layers, of alpha helices and resembles the dinucleotide binding Rossmann fold. One, face of the molecule bears a wide depression that is lined by a number of, strictly conserved residues, and this feature suggests that this is where, substrate binding and catalysis take place. CONCLUSIONS: Through, comparisons with a number of structural homologs, we have assigned, plausible functions to several of the residues that line the substrate, binding pocket. The enzymatic mechanism probably proceeds via a, nucleophilic attack by MPT on the GMP donor, most likely GTP, to produce, MGD and pyrophosphate. By analogy with related enzymes, this process is, likely to require magnesium ions.
About this StructureAbout this Structure
1E5K is a Single protein structure of sequence from Escherichia coli with and as ligands. Known structural/functional Sites: and . Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the molybdenum cofactor biosynthesis protein MobA from Escherichia coli at near-atomic resolution., Stevenson CE, Sargent F, Buchanan G, Palmer T, Lawson DM, Structure. 2000 Nov 15;8(11):1115-25. PMID:11080634
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