2fb2

Structure of the MoaA Arg17/266/268/Ala triple mutant

spinqualitylabelsall models 2fb2, resolution 2.25Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2fb2 is a 2 chain structure with sequence from Staphylococcus aureus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.25Å Ligands: SAM, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function MOAA_STAA8 Catalyzes, together with MoaC, the conversion of 5'-GTP to cyclic pyranopterin monophosphate (cPMP or molybdopterin precursor Z). 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 PubMed The first step in molybdenum cofactor biosynthesis, the conversion of 5'-GTP to precursor Z, an oxygen-sensitive tetrahydropyranopterin is catalyzed by the S-adenosylmethionine (SAM)-dependent enzyme MoaA and the accessory protein MoaC. This reaction involves the radical-initiated intramolecular rearrangement of the guanine C8 atom. MoaA harbors an N-terminal [4Fe-4S] cluster, which is involved in the reductive cleavage of SAM and generates a 5'-deoxyadenosyl radical (5'-dA*), and a C-terminal [4Fe-4S] cluster presumably involved in substrate binding and/or activation. Biochemical studies identified residues involved in 5'-GTP binding and the determinants of nucleotide specificity. The crystal structure of MoaA in complex with 5'-GTP confirms the biochemical data and provides valuable insights into the subsequent radical reaction. MoaA binds 5'-GTP with high affinity and interacts through its C-terminal [4Fe-4S] cluster with the guanine N1 and N2 atoms, in a yet uncharacterized binding mode. The tightly anchored triphosphate moiety prevents the escape of radical intermediates. This structure also visualizes the L-Met and 5'-dA cleavage products of SAM. Rotation of the 5'-dA ribose and/or conformational changes of the guanosine are proposed to bring the 5'-deoxyadenosyl radical into close proximity of either the ribose C2' and C3' or the guanine C8 carbon atoms leading to hydrogen abstraction. Binding of 5'-GTP to the C-terminal FeS cluster of the radical S-adenosylmethionine enzyme MoaA provides insights into its mechanism.,Hanzelmann P, Schindelin H Proc Natl Acad Sci U S A. 2006 May 2;103(18):6829-34. Epub 2006 Apr 21. PMID:16632608 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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