Mutation of His-105 in the beta 1 subunit yields a nitric oxide-insensitive form of soluble guanylyl cyclase.
Soluble guanylyl cyclase [GTP pyrophosphate-lyase (cyclizing); EC 4.6.1.2] is a hemoprotein that exists as a heterodimer; the heme moiety has been proposed to bind nitric oxide, resulting in a dramatic activation of the enzyme. Mutation of six conserved His residues reduced but did not abolish nitric oxide stimulation whereas a change of His-105 to Phe in the beta 1 subunit yielded a heterodimer that retained basal cyclase activity but failed to respond to nitric oxide. Heme was not detected as a component of the mutant heterodimer and protophorphyrin IX failed to stimulate enzyme activity. The activity of the His mutant was almost identical to that of the wild-type enzyme in the presence of KCN, suggesting that disruption of heme binding is the principal effect of the mutation. Thus, the mutation provides a means to inhibit the nitric oxide-sensitive guanylyl cyclase signaling pathway.
Wedel
B
B
Institut für Pharmakologie, Freie Universität Berlin, Federal Republic of Germany.
Humbert
P
P
Harteneck
C
C
Foerster
J
J
Malkewitz
J
J
Böhme
E
E
Schultz
G
G
Koesling
D
D
D000595:Amino Acid Sequence; D000818:Animals; D006152:Cyclic GMP / Q000096:biosynthesis; D004789:Enzyme Activation / Q000187:drug effects; D005978:Glutathione / Q000031:analogs & derivatives / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000378:metabolism; D006162:Guanylate Cyclase / Q000187:drug effects* / Q000235:genetics; D006418:Heme / Q000032:analysis; D006639:Histidine / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D009569:Nitric Oxide / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology; D026422:S-Nitrosoglutathione; D013053:Spectrophotometry
D009603:Nitroso Compounds; D009599:Nitroprusside; D009569:Nitric Oxide; D006418:Heme; D006639:Histidine; D026422:S-Nitrosoglutathione; D006160:Guanosine Triphosphate; D006162:Guanylate Cyclase; D005978:Glutathione; D006152:Cyclic GMP