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Probing Heme Coordination States of Inducible Nitric Oxide Synthase with a Re(I)(imidazole-alkyl-nitroarginine) Sensitizer-Wire

Nguyen, Yen Hoang Le and Winkler, Jay R. and Gray, Harry B. (2007) Probing Heme Coordination States of Inducible Nitric Oxide Synthase with a Re(I)(imidazole-alkyl-nitroarginine) Sensitizer-Wire. Journal of Physical Chemistry B, 111 (24). pp. 6628-6633. ISSN 1520-6106. PMCID PMC2596599. https://resolver.caltech.edu/CaltechAUTHORS:20170531-130123854

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Abstract

Mammalian inducible nitric oxide synthase (iNOS) catalyzes the production of L-citrulline and nitric oxide (NO) from L-arginine and O_2. The Soret peak in the spectrum of the iNOS heme domain (iNOS_(oxy)) shifts from 423 to 390 nm upon addition of a sensitizer-wire, [Re^I-imidazole-(CH_2)_8-nitroarginine]^+, or [ReC_8argNO_2]^+, owing to partial displacement of the water ligand in the active site. From analysis of competitive binding experiments with imidazole, the dissociation constant (K_d) for [ReC_8argNO_2]^+−iNOS_(oxy) was determined to be 3.0 ± 0.1 μM, confirming that the sensitizer-wire binds with higher affinity than both L-arginine (K_d = 22 ± 5 μM) and imidazole (K_d = 14 ± 3 μM). Laser excitation (355 nm) of [ReC_8argNO_2]^+−iNOS_(oxy) triggers electron transfer to the active site of the enzyme, producing a ferroheme in less than ∼1 μs.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/jp071405+DOIArticle
http://pubs.acs.org/doi/abs/10.1021/jp071405%2BPublisherArticle
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2596599/PubMed CentralArticle
ORCID:
AuthorORCID
Winkler, Jay R.0000-0002-4453-9716
Gray, Harry B.0000-0002-7937-7876
Additional Information:© 2007 American Chemical Society. Received: February 19, 2007; In Final Form: April 4, 2007. Publication Date (Web): May 31, 2007. We thank Professor Michael Marletta for materials and assistance in connection with the iNOSoxy preparation. Our work was supported by NIH and the Ellison Medical Foundation (Senior Scholar in Aging to H.B.G.).
Funders:
Funding AgencyGrant Number
NIHUNSPECIFIED
Ellison Medical FoundationUNSPECIFIED
Issue or Number:24
PubMed Central ID:PMC2596599
Record Number:CaltechAUTHORS:20170531-130123854
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170531-130123854
Official Citation:Probing Heme Coordination States of Inducible Nitric Oxide Synthase with a Re(I)(imidazole-alkyl-nitroarginine) Sensitizer-Wire Yen Hoang Le Nguyen, Jay R. Winkler, and Harry B. Gray The Journal of Physical Chemistry B 2007 111 (24), 6628-6633 DOI: 10.1021/jp071405+
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:77859
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:31 May 2017 20:21
Last Modified:22 Nov 2019 09:58

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