Nanosecond photoreduction of inducible nitric oxide synthase by a Ru-diimine electron tunneling wire bound distant from the active site.
A Ru-diimine wire, [(4,4',5,5'-tetramethylbipyridine)2Ru(F9bp)]2+ (tmRu-F9bp, where F9bp is 4-methyl-4'-methylperfluorobiphenylbipyridine), binds tightly to the oxidase domain of inducible nitric oxide synthase (iNOSoxy). The binding of tmRu-F9bp is independent of tetrahydrobiopterin, arginine, and imidazole, indicating that the wire resides on the surface of the enzyme, distant from the active-site heme. Photoreduction of an imidazole-bound active-site heme iron in the enzyme-wire conjugate (k(ET) = 2(1) x 10(7) s(-1)) is fully seven orders of magnitude faster than the in vivo process.
Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA.
Charlotte A
CA
Whited
Wendy
W
Belliston-Bittner
Alexander R
AR
Dunn
Jay R
JR
Winkler
Harry B
HB
Gray
D020134:Catalytic Domain; D004583:Electrons; D006801:Humans; D007097:Imines; D008024:Ligands; D052247:Nitric Oxide Synthase Type II / Q000737:chemistry* / Q000528:radiation effects; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D011485:Protein Binding; D012428:Ruthenium
D007097:Imines; D008024:Ligands; D012428:Ruthenium; D052247:Nitric Oxide Synthase Type II