Direct fusion of subunits of heterodimeric nitric oxide sensitive guanylyl cyclase leads to functional enzymes with preserved biochemical properties: evidence for isoform specific activation by ciguates.

Nitric oxide sensitive guanylyl cyclase (NOsGC) is a heterodimeric enzyme consisting of an α and a β subunit. Two heterodimeric enzymes are known to be important for NO-signalling in humans: α(1)/β(1) and α(2)/β(1). No difference had so far been detected with respect to their pharmacological properties, but as we show in the present paper the new drugs cinaciguat and ataciguat activate the α(1)/β(1) form more effectively.

Fluorescent fusion proteins of soluble guanylyl cyclase indicate proximity of the heme nitric oxide domain and catalytic domain.

Background: To examine the structural organisation of heterodimeric soluble guanylyl cyclase (sGC) Förster resonance energy transfer (FRET) was measured between fluorescent proteins fused to the amino- and carboxy-terminal ends of the sGC beta1 and alpha subunits.

Methodology/principal Findings: Cyan fluorescent protein (CFP) was used as FRET donor and yellow fluorescent protein (YFP) as FRET acceptor. After generation of recombinant baculovirus, fluorescent-tagged sGC subunits were co-expressed in Sf9 cells.