Document Detail

Direct electrochemistry of Shewanella oneidensis cytochrome c nitrite reductase: evidence of interactions across the dimeric interface.
MedLine Citation:
PMID:  23210513     Owner:  NLM     Status:  MEDLINE    
Shewanella oneidensis cytochrome c nitrite reductase (soNrfA), a dimeric enzyme that houses five c-type hemes per protomer, conducts the six-electron reduction of nitrite and the two-electron reduction of hydroxylamine. Protein film voltammetry (PFV) has been used to study the cytochrome c nitrite reductase from Escherichia coli (ecNrfA) previously, revealing catalytic reduction of both nitrite and hydroxylamine substrates by ecNrfA adsorbed to a graphite electrode that is characterized by "boosts" and attenuations in activity depending on the applied potential. Here, we use PFV to investigate the catalytic properties of soNrfA during both nitrite and hydroxylamine turnover and compare those properties to the properties of ecNrfA. Distinct differences in both the electrochemical and kinetic characteristics of soNrfA are observed; e.g., all detected electron transfer steps are one-electron in nature, contrary to what has been observed in ecNrfA [Angove, H. C., Cole, J. A., Richardson, D. J., and Butt, J. N. (2002) J. Biol. Chem. 277, 23374-23381]. Additionally, we find evidence of substrate inhibition during nitrite turnover and negative cooperativity during hydroxylamine turnover, neither of which has previously been observed in any cytochrome c nitrite reductase. Collectively, these data provide evidence that during catalysis, potential pathways of communication exist between the individual soNrfA monomers comprising the native homodimer.
Evan T Judd; Matthew Youngblut; A Andrew Pacheco; Sean J Elliott
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2012-12-12
Journal Detail:
Title:  Biochemistry     Volume:  51     ISSN:  1520-4995     ISO Abbreviation:  Biochemistry     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-12-21     Completed Date:  2013-02-19     Revised Date:  2014-01-09    
Medline Journal Info:
Nlm Unique ID:  0370623     Medline TA:  Biochemistry     Country:  United States    
Other Details:
Languages:  eng     Pagination:  10175-85     Citation Subset:  IM    
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MeSH Terms
Cytochromes a1 / chemistry,  metabolism*
Cytochromes c1 / chemistry,  metabolism*
Electron Transport
Escherichia coli / enzymology
Hydroxylamine / metabolism
Nitrate Reductases / chemistry,  metabolism*
Nitrites / metabolism*
Protein Multimerization
Shewanella / enzymology*
Grant Support
Reg. No./Substance:
0/Nitrites; 2FP81O2L9Z/Hydroxylamine; 9035-35-2/Cytochromes a1; 9035-42-1/Cytochromes c1; EC 1.7.-/Nitrate Reductases; EC reductase (cytochrome)

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