Ancient conserved domains shared by animal soluble guanylyl cyclases and bacterial signaling proteins.

ABSTRACT: BACKGROUND:Soluble guanylyl cyclases (SGCs) are dimeric enzymes that transduce signals downstream of nitric oxide (NO) in animals. They sense NO by means of a heme moiety that is bound to their N-terminal extensions. RESULTS:Using sequence profile searches we show that the N-terminal extensions of the SGCs contain two globular domains. The first of these, the HNOB (Heme NO Binding) domain, is a predominantly alpha-helical domain and binds heme via a covalent linkage to histidine. Versions lacking this conserved histidine and are likely to interact with heme non-covalently. We detected HNOB domains in several bacterial lineages, where they occur fused to methyl accepting domains of chemotaxis receptors or as standalone proteins. The standalone forms are encoded by predicted operons that als

SUBMITTER: Iyer LM 

PROVIDER: S-EPMC149354 | biostudies-literature | 2003 Feb

REPOSITORIES: biostudies-literature