4l77: Difference between revisions
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== Function == | == Function == | ||
[https://www.uniprot.org/uniprot/CINA_CITBR CINA_CITBR] Involved in the degradation of cineol (eucalyptol). Catalyzes the initial hydroxylation of cineole exclusively at the pro-R carbon to give the (S)-6beta-hydroxycineole. Cineole is the natural substrate of CinA. | [https://www.uniprot.org/uniprot/CINA_CITBR CINA_CITBR] Involved in the degradation of cineol (eucalyptol). Catalyzes the initial hydroxylation of cineole exclusively at the pro-R carbon to give the (S)-6beta-hydroxycineole. Cineole is the natural substrate of CinA. | ||
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== Publication Abstract from PubMed == | |||
In P450cin, Tyr81, Asp241, Asn242, two water molecules, and the substrate participate in a complex H-bonded network. The role of this H-bonded network in substrate binding and catalysis has been probed by crystallography, spectroscopy, kinetics, isothermal titration calorimetry (ITC), and molecular dynamics. For the Y81F mutant, the substrate binds about 20-fold more weakly and Vmax decreases by about 30% in comparison to WT. The enhanced susceptibility of the heme to H2O2-mediated destruction in Y81F suggests that this mutant favors the open, low-spin conformational state. Asn242 H-bonds directly with the substrate, and replacing this residue with Ala results in water taking the place of the missing Asn side chain. This mutant exhibits a 70% decrease in activity. Crystal structures and molecular dynamics simulations of substrate-bound complexes show that the solvent has more ready access to the active site, especially for the N242A mutant. This accounts for about a 64% uncoupling of electron transfer from substrate hydroxylation. These data indicate the importance of the interconnected water network on substrate binding and on the open/closed conformational equilibrium, which are both critically important for maintaining high-coupling efficiency. | |||
P450cin Active Site Water: Implications for Substrate Binding and Solvent Accessibility.,Madrona Y, Hollingsworth SA, Khan B, Poulos TL Biochemistry. 2013 Jul 18. PMID:23829586<ref>PMID:23829586</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
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==See Also== | ==See Also== | ||
*[[Cytochrome P450 3D structures|Cytochrome P450 3D structures]] | *[[Cytochrome P450 3D structures|Cytochrome P450 3D structures]] | ||
== References == | |||
<references/> | |||
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</StructureSection> | </StructureSection> | ||
