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| [[Image:2iz5.gif|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_2iz5| PDB=2iz5 | SCENE= }} | | {{STRUCTURE_2iz5| PDB=2iz5 | SCENE= }} |
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| '''FUNCTION AND STRUCTURE OF THE MOLYBDENUM COFACTOR CARRIER PROTEIN MCP FROM CHLAMYDOMONAS REINHARDTII'''
| | ===FUNCTION AND STRUCTURE OF THE MOLYBDENUM COFACTOR CARRIER PROTEIN MCP FROM CHLAMYDOMONAS REINHARDTII=== |
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| ==Overview==
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| 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. | | The line below this paragraph, {{ABSTRACT_PUBMED_16873364}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 16873364 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_16873364}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Metal transport]] | | [[Category: Metal transport]] |
| [[Category: Molybdenum cofactor]] | | [[Category: Molybdenum cofactor]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 08:06:31 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 07:25:49 2008'' |
