PMID- 20353168 OWN - NLM STAT- MEDLINE DCOM- 20100525 LR - 20211020 IS - 1520-4995 (Electronic) IS - 0006-2960 (Print) IS - 0006-2960 (Linking) VI - 49 IP - 18 DP - 2010 May 11 TI - Probing soluble guanylate cyclase activation by CO and YC-1 using resonance Raman spectroscopy. PG - 3815-23 LID - 10.1021/bi902214j [doi] AB - Soluble guanylate cyclase (sGC) is weakly activated by carbon monoxide (CO) but is significantly activated by the binding of YC-1 to the sGC-CO complex. In this report, resonance Raman (RR) spectroscopy was used to study selected sGC variants. Addition of YC-1 to the sGC-CO complex alters the intensity pattern of RR bands assigned to the vinyl and propionate heme substituents, suggesting changes in the tilting of the pyrrole rings to which they are attached. YC-1 also shifts the RR intensity of the nu(FeC) and nu(CO) bands from 473 and 1985 cm(-1) to 487 and 1969 cm(-1), respectively, and induces an additional nu(FeC) band, at 521 cm(-1), assigned to five-coordinate heme-CO. Site-directed variants in the proximal heme pocket (P118A) or in the distal heme pocket (V5Y and I149Y) reduce the extent of YC-1 activation, along with the 473 cm(-1) band intensity. These lower-activity sGC variants display another nu(FeC) band at 493 cm(-1) which is insensitive to YC-1 addition and is attributed to protein that cannot be activated by the allosteric activator. The results are consistent with a model in which YC-1 binding to the sGC-CO complex results in a conformational change that activates the protein. Specifically, YC-1 binding alters the heme geometry via peripheral nonbonded contacts and also relieves an intrinsic electronic effect that weakens FeCO backbonding in the native, YC-1 responsive protein. This electronic effect might involve neutralization of the heme propionates via H-bond contacts or negative polarization by a distal cysteine residue. YC-1 binding also strains the Fe-histidine bond, leading to a population of the five-coordinate sGC-CO complex in addition to a conformationally distinct population of the six-coordinate sGC-CO complex. The loss of YC-1 activation in the sGC variants might involve a weakening of the heme-protein contacts that are thought to be critical to a YC-1-induced conformational change. FAU - Ibrahim, Mohammed AU - Ibrahim M AD - Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA. FAU - Derbyshire, Emily R AU - Derbyshire ER FAU - Marletta, Michael A AU - Marletta MA FAU - Spiro, Thomas G AU - Spiro TG LA - eng GR - GM033576/GM/NIGMS NIH HHS/United States GR - R01 GM077365/GM/NIGMS NIH HHS/United States GR - R01 GM033576-41/GM/NIGMS NIH HHS/United States GR - GM077365/GM/NIGMS NIH HHS/United States GR - R01 GM033576/GM/NIGMS NIH HHS/United States PT - Evaluation Study PT - Journal Article PT - Research Support, N.I.H., Extramural PL - United States TA - Biochemistry JT - Biochemistry JID - 0370623 RN - 0 (Indazoles) RN - 0 (Receptors, Cytoplasmic and Nuclear) RN - 154453-18-6 (3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole) RN - 42VZT0U6YR (Heme) RN - 7U1EE4V452 (Carbon Monoxide) RN - EC 4.6.1.2 (Guanylate Cyclase) RN - EC 4.6.1.2 (Soluble Guanylyl Cyclase) SB - IM MH - Animals MH - Binding Sites MH - Carbon Monoxide/*chemistry/metabolism MH - Enzyme Activation MH - Guanylate Cyclase/*chemistry/genetics/metabolism MH - Heme/chemistry/metabolism MH - Indazoles/*chemistry/metabolism MH - Kinetics MH - Protein Binding MH - Protein Structure, Tertiary MH - Rats MH - Receptors, Cytoplasmic and Nuclear/*chemistry/genetics/metabolism MH - Soluble Guanylyl Cyclase MH - Spectrum Analysis, Raman PMC - PMC2894327 MID - NIHMS197343 EDAT- 2010/04/01 06:00 MHDA- 2010/05/26 06:00 PMCR- 2011/05/11 CRDT- 2010/04/01 06:00 PHST- 2010/04/01 06:00 [entrez] PHST- 2010/04/01 06:00 [pubmed] PHST- 2010/05/26 06:00 [medline] PHST- 2011/05/11 00:00 [pmc-release] AID - 10.1021/bi902214j [doi] PST - ppublish SO - Biochemistry. 2010 May 11;49(18):3815-23. doi: 10.1021/bi902214j.