Abstract
Electron-transfer kinetics have been measured in four conjugates of cytochrome P450 with surface-bound Ru-photosensitizers. The conjugates are constructed with enzymes from Bacillus megaterium (CYP102A1) and Sulfolobus acidocaldarius (CYP119). A W96 residue lies in the path between Ru and the heme in CYP102A1, whereas H76 is present at the analogous location in CYP119. Two additional conjugates have been prepared with (CYP102A1)W96H and (CYP119)H76W mutant enzymes. Heme oxidation by photochemically generated Ru3+ leads to P450 compound II formation when a tryptophan residue is in the path between Ru and the heme; no heme oxidation is observed when histidine occupies this position. The data indicate that heme oxidation proceeds via two-step tunneling through a tryptophan radical intermediate. In contrast, heme reduction by photochemically generated Ru+ proceeds in a single electron tunneling step with closely similar rate constants for all four conjugates.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
