Crystal structures of human soluble guanylate cyclase catalytic domains: promiscuity of the dimer interface and a potential allosteric site

Background Soluble guanylate cyclase (sGC) catalyses the synthesis of cyclic GMP in response to nitric oxide. The enzyme is a heterodimer of homologous a and b subunits, each of which is composed of multiple domains. Results We present here crystal structures of a heterodimer of the catalytic domains of the a and b subunits, as well as an inactive homodimer of b subunits. This first structure of a metazoan, heteromeric cyclase provides several