Document Detail

Resonance Raman evidence for the presence of two heme pocket conformations with varied activities in CO-bound bovine soluble guanylate cyclase and their conversion.
MedLine Citation:
PMID:  15654750     Owner:  NLM     Status:  MEDLINE    
Resonance Raman (RR) spectra of soluble guanylate cyclase (sGC) reported by five independent research groups have been classified as two types: sGC(1) and sGC(2). Here we demonstrate that the RR spectra of sGC isolated from bovine lung contain only sGC(2) while both species are observed in the spectra of the CO-bound form (CO-sGC). The relative populations of the two forms were altered from an initial composition in which the CO-sGC(2) form predominated, with the Fe-CO (nu(Fe)(-)(CO)) and C-O stretching modes (nu(CO)) at 472 and 1985 cm(-)(1), respectively, to a composition dominated by the CO-sGC(1) form with nu(Fe)(-)(CO) and nu(CO) at 488 and 1969 cm(-)(1), respectively, following the addition of a xenobiotic, YC-1. Further addition of a substrate, GTP, completed the change. GDP and cGMP had a significantly weaker effect, while a substrate analogue, GTP-gamma-S, had an effect similar to that of GTP. In contrast, ATP had a reverse effect, and suppressed the effects of YC-1 and GTP. In the presence of both YC-1 and GTP, vinyl vibrations of heme were significantly influenced. New CO isotope-sensitive bands were observed at 521, 488, 363, and 227 cm(-)(1). The 521 cm(-)(1) band was assigned to the five-coordinate (5c) species from the model compound studies using ferrous iron protoporphyrin IX in CTAB micelles. Distinct from the 472 cm(-)(1) species, both the 488 and 521 cm(-)(1) species were apparently un-photodissociable when an ordinary Raman spinning cell was used, indicating rapid recombination of photodissociated CO. On the basis of these findings, binding of YC-1 to the heme pocket is proposed.
Zhengqiang Li; Biswajit Pal; Shigeo Takenaka; Shingo Tsuyama; Teizo Kitagawa
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Biochemistry     Volume:  44     ISSN:  0006-2960     ISO Abbreviation:  Biochemistry     Publication Date:  2005 Jan 
Date Detail:
Created Date:  2005-01-18     Completed Date:  2005-04-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0370623     Medline TA:  Biochemistry     Country:  United States    
Other Details:
Languages:  eng     Pagination:  939-46     Citation Subset:  IM    
Okazaki Institute for Integrative Bioscience, National Institute of Natural Sciences, Myodaiji, Okazaki 444-8787, Japan.
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MeSH Terms
Allosteric Regulation
Carbon Monoxide / metabolism*
Guanine Nucleotides / metabolism
Guanylate Cyclase / metabolism*
Heme / metabolism*
Protein Binding
Spectrum Analysis, Raman
Reg. No./Substance:
0/Guanine Nucleotides; 14875-96-8/Heme; 630-08-0/Carbon Monoxide; EC Cyclase

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