1iwk | pdb_00001iwk

Putidaredoxin-Binding Stablilizes an Active Conformer of Cytochrome P450cam in its Reduced State; Crystal Structure of Mutant(112K) Cytochrome P450cam

spinqualitylabelsall models 1iwk, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1iwk is a 1 chain structure with sequence from Pseudomonas putida. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: HEM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT, TOPSAN Function CPXA_PSEPU Involved in a camphor oxidation system. 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 Ferrous-carbon monoxide bound form of cytochrome P450cam (CO-P450cam) has two infrared (IR) CO stretching bands at 1940 and 1932 cm(-1). The former band is dominant (>95% in area) for CO-P450cam free of putidaredoxin (Pdx), while the latter band is dominant (>95% in area) in the complex of CO-P450cam with reduced Pdx. The binding of Pdx to CO-P450cam thus evokes a conformational change in the heme active site. To study the mechanism involved in the conformational change, surface amino acid residues Arg79, Arg109, and Arg112 in P450cam were replaced with Lys, Gln, and Met. IR spectroscopic and kinetic analyses of the mutants revealed that an enzyme that has a larger 1932 cm(-1) band area upon Pdx-binding has a larger catalytic activity. Examination of the crystal structures of R109K and R112K suggested that the interaction between the guanidium group of Arg112 and Pdx is important for the conformational change. The mutations did not change a coupling ratio between the hydroxylation product and oxygen consumed. We interpret these findings to mean that the interaction of P450cam with Pdx through Arg112 enhances electron donation from the proximal ligand (Cys357) to the O-O bond of iron-bound O(2) and, possibly, promotes electron transfer from reduced Pdx to oxyP450cam, thereby facilitating the O-O bond splitting. Infrared spectroscopic and mutational studies on putidaredoxin-induced conformational changes in ferrous CO-P450cam.,Nagano S, Shimada H, Tarumi A, Hishiki T, Kimata-Ariga Y, Egawa T, Suematsu M, Park SY, Adachi S, Shiro Y, Ishimura Y Biochemistry. 2003 Dec 16;42(49):14507-14. PMID:14661963 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cytochrome P450 3D structures

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