The nitric oxide (NO) signaling
pathway is important for many physiological functions including
vascular smooth muscle relaxation, neuronal signal transduction and
inhibition of platelet aggregation. The source of NO in vivo
is the enzyme nitric oxide synthase. The
principal receptor for NO is soluble guanylate cyclase (sGC), which
catalyzes the conversion of GTP to the second messenger molecule cyclic
GMP (cGMP). sGC is a member of a family of related enzymes which
share homologous catalytic domains, but are activated in different
ways. This family includes the adenylate cyclases, a class of
membrane bound enzymes that convert ATP to cAMP and are regulated by G
proteins, and the membrane-bound guanylate cyclases that make cGMP in
response to hormone signals via an extracellular ligand binding domain.
sGC is a heterodimeric
hemoprotein consisting of homologous alpha and beta subunits.
Each subunit consists of a N-terminal H-NOX
domain, a central domain of unknown function, and a C-terminal
consensus nucleotide cyclase domain. When NO binds to the heme
prosthetic group in the beta subunit of sGC, catalysis is accelerated
by 2-3 orders of magnitude.
 1. How does the binding of NO affect the heme and surrounding environment? 2. How is the NO binding event translated into increased catalytic activity? 3. How does sGC deactivate? 4. How do other small molecules such as carbon monoxide (CO), YC-1, and organic nitrogen oxides activate sGC? 5. How do nucleotides regulate sGC activity? Additionally, we have
initiated a series of experiments to characterize novel guanylate
cyclases in C. elegans and Drosophila. We have
identified some of these putative cyclases through sequence analyses
and cloned them, and are currently involved in both biochemical and in
vivo characterization. References (1) Derbyshire, ER; Fernhoff, NB; Deng, S; Marletta, MA. Nucleotide Regulation of Soluble Guanylate Cyclase Substrate Specificity. Biochemistry 2009, Epub ahead of print. (2) Zimmer M; Gray JM; Pokala N; Chang AJ; Karow DS; Marletta MA; Hudson ML; Morton DB; Chronis N; Bargmann Cl. Neurons detect increases and decreases in oxygen levels using distinct guanylate cyclases. Neuron 2009, 61:865-79. (3) Derbyshire ER; Marletta MA. Biochemistry of soluble guanylate cyclase. Handb. Exp. Pharmacol. 2009, 191, 17-31. Rev. (4) Derbyshire, ER; Gunn, A; Ibrahim, M; Spiro, TG.; Britt, RD; Marletta, MA. Characterization of Two Different Five-Coordinate Soluble Guanylate Cyclase Ferrous-Nitrosyl Complexes. Biochemistry 2008, 47, 3892-9. (5) Derbyshire, ER; Marletta, MA. Butyl Isocyanide as a Probe of the Activation Mechanism of Soluble Guanylate Cyclase: investigating the role of non-heme nitric oxide. J. Biol. Chem. 2007, 282, 35741-8. (6) Huang, SH; Rio, DC; Marletta, MA. Ligand Binding and Inhibition of an Oxygen-Sensitive Soluble Guanylate Cyclase, Gyc-88E, from Drosophila. Biochemistry 2007, 46, 15115-22. (7) Winger, JA; Derbyshire, ER; Marletta, MA. Dissociation of Nitric Oxide from Soluble Guanylate Cyclase and Heme-Nitric Oxide/Oxygen Binding Domain Constructs. J. Biol. Chem. 2007, 282, 897-907. (8) Hering, KW; Artz, JD; Pearson, WH; Marletta, MA. The design and synthesis of YC-1 analogues as probes for soluble guanylate cyclase. Bioorg Med. Chem. Lett. 2006, 16, 618-21. (9) Karow, DS; Pan, D; Davis, JH; Behrends, S; Mathies, RA; Marletta, MA. Characterization of functional heme domains from soluble guanylate cyclase. Biochemistry. 2005, 44, 16266-74. (10) Derbyshire, ER; Tran, R; Mathies, RA; Marletta, MA. Characterization of nitrosoalkane binding and activation of soluble guanylate cyclase. Biochemistry. 2005, 44, 16257-65. (11) Cary, SP; Winger, JA; Marletta, MA. Tonic and acute nitric oxide signaling through soluble guanylate cyclase is mediated by nonheme nitric oxide, ATP, and GTP. Proc. Natl. Acad. Sci. U S A. 2005, 102,13064-9. (12) Winger, JA; Marletta, MA. Expression and characterization of the catalytic domains of soluble guanylate cyclase: interaction with the heme domain. Biochemistry. 2005, 44, 4083-90. (13) Gray, JM; Karow, DS; Lu, H; Chang, AJ; Chang, JS; Ellis, RE; Marletta, MA; Bargmann, CI. Oxygen sensation and social feeding mediated by a C. elegans guanylate cyclase homologue. Nature. 2004, 430, 317-22. (14) Ballou, DP; Zhao, Y; Brandish, PE; Marletta, MA. Revisiting the kinetics of nitric oxide (NO) binding to soluble guanylate cyclase: the simple NO-binding model is incorrect. Proc. Natl. Acad. Sci. USA 2002, 99, 12097-101. (15) Artz, JD; Schmidt, B; McCracken, JL; Marletta, MA. Effects of nitroglycerin on soluble guanylate cyclase: implications for nitrate tolerance. J. Biol. Chem. 2002, 277, 18253-6. (16) Denninger, JW; Schelvis, JP; Brandish, PE; Zhao, Y; Babcock, GT; Marletta, MA. Interaction of soluble guanylate cyclase with YC-1: kinetic and resonance Raman studies. Biochemistry 2000, 39, 4191-8. Home │Research │ People │ Publications │Lab Links │Contact Info |
