2iz6

Structure of the Chlamydomonas rheinhardtii Moco Carrier Protein

spinqualitylabelsall models 2iz6, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2iz6 is a 2 chain structure with sequence from Chlamydomonas reinhardtii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.6Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q8RV61_CHLRE 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 molybdenum cofactor (Moco) forms the catalytic site in all eukaryotic molybdenum enzymes and is synthesized by a multistep biosynthetic pathway. The mechanism of transfer, storage, and insertion of Moco into the appropriate apo-enzyme is poorly understood. In Chlamydomonas reinhardtii, a Moco carrier protein (MCP) has been identified and characterized recently. Here we show biochemical evidence that MCP binds Moco as well as the tungstate-substituted form of the cofactor (Wco) with high affinity, whereas molybdopterin, the ultimate cofactor precursor, is not bound. This binding selectivity points to a specific metal-mediated interaction with MCP, which protects Moco and Wco from oxidation with t((1/2)) of 24 and 96 h, respectively. UV-visible spectroscopy showed defined absorption bands at 393, 470, and 570 nm pointing to ene-diothiolate and protein side-chain charge transfer bonds with molybdenum. We have determined the crystal structure of MCP at 1.6 Angstrom resolution using seleno-methionated and native protein. The monomer constitutes a Rossmann fold with two homodimers forming a symmetrical tetramer in solution. Based on conserved surface residues, charge distribution, shape, in silico docking studies, structural comparisons, and identification of an anionbinding site, a prominent surface depression was proposed as a Moco-binding site, which was confirmed by structure-guided mutagenesis coupled to substrate binding studies. Function and structure of the molybdenum cofactor carrier protein from Chlamydomonas reinhardtii.,Fischer K, Llamas A, Tejada-Jimenez M, Schrader N, Kuper J, Ataya FS, Galvan A, Mendel RR, Fernandez E, Schwarz G J Biol Chem. 2006 Oct 6;281(40):30186-94. Epub 2006 Jul 27. PMID:16873364 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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