2iz7
From Proteopedia
| |||||||
| , resolution 2.32Å | |||||||
|---|---|---|---|---|---|---|---|
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
STRUCTURE OF MOCO CARRIER PROTEIN FROM CHLAMYDOMONAS REINHARDTII
Overview
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.
About this Structure
2IZ7 is a Single protein structure of sequence from Chlamydomonas reinhardtii. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Mon Mar 31 03:50:45 2008
