FIGURE 1.

Positions of the five tryptophan residues in rat NOsGC subunits. Tryptophan residues are marked as purple rings. Amino acids 692–699 represent the Strep-tag II (S) containing an additional tryptophan residue. The red rhombus indicates position of the heme group. The schematic representation of functional domains is based on the crystallized region of the HNOX domain of Alr2278 from Nostoc sp. (PCC 7120) (32) on the crystallized region of PAS domain of signal transduction histidine kinase from Nostoc punctiforme (PCC 73102) (33) on the crystallized region of the coiled-coil domain of the NOsGC β₁ subunit from Rattus norvegicus (24) and on the crystallized catalytic region of the guanylate cyclase CYG12 from Chlamydomonas reinhardtii (34).