1qlm

The crystal structure of methenyltetrahydromethanopterin cyclohydrolase from the hyperthermophilic archaeon Methanopyrus kandleri

spinqualitylabelsall models 1qlm, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1qlm is a 1 chain structure with sequence from Dsm 6324. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: PO4 Activity: Methenyltetrahydromethanopterin cyclohydrolase, with EC number 3.5.4.27 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [MCH_METKA] Catalyzes the reversible interconversion of 5-formyl-H(4)MPT to methenyl-H(4)MPT(+). 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 BACKGROUND: The reduction of carbon dioxide to methane in methanogenic archaea involves the tetrahydrofolate analogue tetrahydromethanopterin (H(4)MPT) as a C(1) unit carrier. In the third step of this reaction sequence, N(5)-formyl-H(4)MPT is converted to methenyl-H(4)MPT(+) by the enzyme methenyltetrahydromethanopterin cyclohydrolase. The cyclohydrolase from the hyperthermophilic archaeon Methanopyrus kandleri (Mch) is extremely thermostable and adapted to a high intracellular concentration of lyotropic salts. RESULTS: Mch was crystallized and its structure solved at 2.0 A resolution using a combination of the single isomorphous replacement (SIR) and multiple anomalous dispersion (MAD) techniques. The structure of the homotrimeric enzyme reveals a new alpha/beta fold that is composed of two domains forming a large sequence-conserved pocket between them. Two phosphate ions were found in and adjacent to this pocket, respectively; the latter is displaced by the phosphate moiety of the substrate formyl-H(4)MPT according to a hypothetical model of the substrate binding. CONCLUSIONS: Although the exact position of the substrate is not yet known, the residues lining the active site of Mch could be tentatively assigned. Comparison of Mch with the tetrahydrofolate-specific cyclohydrolase/dehydrogenase reveals similarities in domain arrangement and in some active-site residues, whereas the fold appears to be different. The adaptation of Mch to high salt concentrations and high temperatures is reflected by the excess of acidic residues at the trimer surface and by the higher oligomerization state of Mch compared with its mesophtic counterparts. The crystal structure of methenyltetrahydromethanopterin cyclohydrolase from the hyperthermophilic archaeon Methanopyrus kandleri.,Grabarse W, Vaupel M, Vorholt JA, Shima S, Thauer RK, Wittershagen A, Bourenkov G, Bartunik HD, Ermler U Structure. 1999 Oct 15;7(10):1257-68. PMID:10545331 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cyclohydrolase 3D structures

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