Nitric oxide binding to prokaryotic homologs of the soluble guanylate cyclase beta1 H-NOX domain.

Full Abstract

The heme cofactor in soluble guanylate cyclase (sGC) is a selective receptor for NO, an important signaling molecule in eukaryotes. The sGC heme domain has been localized to the N-terminal 194 amino acids of the beta1 subunit of sGC and is a member of a family of conserved hemoproteins, called the H-NOX family (Heme-Nitric Oxide and/or OXygen-binding domain). Three new members of this family have now been cloned and characterized, two proteins from Legionella pneumophila (L1 H-NOX and L2 H-NOX) and one from Nostoc punctiforme (Np H-NOX). Like sGC, L1 H-NOX forms a 5-coordinate Fe(II)-NO complex. However, both L2 H-NOX and Np H-NOX form temperature-dependent mixtures of 5- and 6-coordinate Fe(II)-NO complexes; at low temperature, they are primarily 6-coordinate, and at high temperature, the equilibrium is shifted toward a 5-coordinate geometry. This equilibrium is fully reversible with temperature in the absence of free NO. This process is analyzed in terms of a thermally labile proximal Fe(II)-His bond and suggests that in both the 5- and 6-coordinate Fe(II)-NO complexes of L2 H-NOX and Np H-NOX, NO is bound in the distal heme pocket of the H-NOX fold. NO dissociation kinetics for L1 H-NOX and L2 H-NOX have been determined and support a model in which NO dissociates from the distal side of the heme in both 5- and 6-coordinate complexes.

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Author information

Author/s: Boon, Elizabeth M (EM); Davis, Joseph H (JH); Tran, Rosalie (R); Karow, David S (DS); Huang, Shirley H (SH); Pan, Duohai (D); Miazgowicz, Michael M (MM); Mathies, Richard A (RA); Marletta, Michael A (MA);

Affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.

Grants: GM070671 (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: 2006-Aug; vol 281 (issue 31) : pp 21892-902

Dates: Created 2006/07/31; Completed 2006/10/16; Revised 2007/11/14;

PMID: 16728401, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Binding Sites
Guanylate Cyclase - metabolism
Heme - metabolism
Kinetics
Legionella pneumophila - enzymology

Legionella pneumophila - enzymology
Nitric Oxide - metabolism
Nostoc - enzymology
Solubility
Temperature

Associated Chemicals: Nitric Oxide (10102-43-9) ; Heme (14875-96-8) ; Guanylate Cyclase (EC 4.6.1.2)

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