Nanosecond photoreduction of inducible nitric oxide synthase by a Ru-diimine electron tunneling wire bound distant from the active site

作者：Whited Charlotte A; Belliston Bittner Wendy; Dunn Alexander R; Winkler Jay R^*; Gray Harry B

来源：Journal of Inorganic Biochemistry, 2009, 103(6): 906-911.

DOI：10.1016/j.jinorgbio.2009.04.001

• Nitric oxide synthase
• Electron transfer
• Tunneling wire
• Ru sensitizer

A Ru-diimine wire, [(4,4',5,5'-tetramethylbipyridine)(2)Ru(F(9)bp)](2 ) (tmRu-F(9)bp, where F9bp is 4-methyl4'-methyl-perfluorobiphenylbipyridine), binds tightly to the oxidase domain of inducible nitric oxide synthase (iNOSoxy). The binding of tmRu-F(9)bp 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.

• 出版日期2009-6