Nucleotide regulation of soluble guanylate cyclase substrate specificity.
Soluble guanylate cyclase (sGC) serves as a receptor for the signaling agent nitric oxide (NO). sGC synthesis of cGMP is regulated by NO, GTP, ATP, and allosteric activators such as YC-1. The guanylate cyclase activity and adenylate cyclase activity of full-length sGC and the sGC catalytic domain constructs (alpha1(cat)beta1(cat)) are reported here. ATP is a mixed-type inhibitor of cGMP production for both sGC and alpha1(cat)beta1(cat), indicating that the C-terminus of sGC contains an allosteric nucleotide binding site. YC-1 did not activate alpha1(cat)beta1(cat) or compete with ATP inhibition of cGMP synthesis, which suggests that YC-1 and ATP bind to distinct sites. alpha1(cat)beta1(cat) and NO-stimulated sGC also synthesize cAMP, but this activity is inhibited by ATP via noncompetitive substrate inhibition and by GTP via mixed-type inhibition. Additionally, the adenylate cyclase activity of purified sGC was inhibited by PC12 lysate, suggesting that an intracellular small molecule or protein regulates this activity in vivo.
Derbyshire
Emily R
ER
Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3220, USA.
Fernhoff
Nathaniel B
NB
Deng
Sarah
S
Marletta
Michael A
MA
D000255:Adenosine Triphosphate / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000502:physiology; D000262:Adenylyl Cyclases / Q000378:metabolism; D000494:Allosteric Regulation / Q000502:physiology; D000495:Allosteric Site / Q000502:physiology; D000818:Animals; D020134:Catalytic Domain; D006160:Guanosine Triphosphate / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D016716:PC12 Cells; D011487:Protein Conformation; D021122:Protein Subunits / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D000071756:Soluble Guanylyl Cyclase; D013379:Substrate Specificity
D021122:Protein Subunits; D018160:Receptors, Cytoplasmic and Nuclear; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D000262:Adenylyl Cyclases; C106670:adenylyl cyclase 1; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase