Dissociation of nitric oxide from soluble guanylate cyclase and heme-nitric oxide/oxygen binding domain constructs.

Full Abstract

Regulation of soluble guanylate cyclase (sGC), the primary NO receptor, is linked to NO binding to the prosthetic heme group. Recent studies have demonstrated that the degree and duration of sGC activation depend on the presence and ratio of purine nucleotides and on the presence of excess NO. We measured NO dissociation from full-length alpha1beta1 sGC, and the constructs beta1(1-194), beta1(1-385), and beta2(1-217), at 37 and 10 degrees C with and without the substrate analogue guanosine-5'-[(alpha,beta-methylene]triphosphate (GMPCPP) or the activator 3-(5'-hydroxymethyl-3'-furyl)-1-benzylindazole (YC-1). NO dissociation from each construct was complex, requiring two exponentials to fit the data. Decreasing the temperature decreased the contribution of the faster exponential for all constructs. Inclusion of YC-1 moderately accelerated NO dissociation from sGC and beta2(1-217) at 37 degrees C and dramatically accelerated NO dissociation from sGC at 10 degrees C. The presence of GMPCPP also dramatically accelerated NO dissociation from sGC at 10 degrees C. This acceleration is due to increases in the observed rate for each exponential and in the contribution of the faster exponential. Increases in the contribution of the faster exponential correlated with higher activation of sGC by NO. These data indicate that the sGC ferrous-nitrosyl complex adopts two 5-coordinate conformations, a lower activity "closed" form, which releases NO slowly, and a higher activity "open" form, which releases NO rapidly. The ratio of these two species affects the overall rate of NO dissociation. These results have implications for the function of sGC in vivo, where there is evidence for two NO-regulated activity states.

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Author information

Author/s: Winger, Jonathan A (JA); Derbyshire, Emily R (ER); Marletta, Michael A (MA);

Affiliation: Department of Medicinal Chemistry, the University of Michigan, Ann Arbor, Michigan 48109, USA.

Grants: GM07767 (Agency:NIGMS NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't

Journal: The Journal of biological chemistry (J Biol Chem), published in United States. (Language: eng)

Reference: 2007-Jan; vol 282 (issue 2) : pp 897-907

Dates: Created 2007/01/08; Completed 2007/03/07; Revised 2007/12/03;

PMID: 17098738, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Animals
Binding Sites - physiology
Cells, Cultured
Enzyme Activation - physiology
Guanylate Cyclase - chemistry; metabolism
Heme - metabolism
Kinetics
Models, Chemical

Models, Chemical
Nitric Oxide - metabolism
Oxygen - metabolism
Protein Structure, Tertiary
Rats
Receptors, Cytoplasmic and Nuclear - chemistry; metabolism
Spodoptera
Temperature

Associated Chemicals: Receptors, Cytoplasmic and Nuclear (0) ; Nitric Oxide (10102-43-9) ; Heme (14875-96-8) ; Oxygen (7782-44-7) ; Guanylate Cyclase (EC 4.6.1.2) ; soluble guanylyl cyclase (EC 4.6.1.2)

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