Faculty Collaboration Database

Reaction of cyanide with cytochrome ba3 from Thermus thermophilus: spectroscopic characterization of the Fe(II)a3-CN.Cu(II)B-CN complex suggests four 14N atoms are coordinated to CuB. Proc Natl Acad Sci U S A 1992 Apr 15;89(8):3195-9

Date

04/15/1992

Pubmed ID

1314380

Pubmed Central ID

PMC48832

DOI

10.1073/pnas.89.8.3195

Scopus ID

2-s2.0-11944264512 (requires institutional sign-in at Scopus site)   49 Citations

Abstract

Cytochrome ba3 from Thermus thermophilus reacts slowly with excess HCN at pH 7.4 to create a form of the enzyme in which CuA, cytochrome b, and CuB remain oxidized, while cytochrome a3 is reduced by one electron, presumably with the formation of cyanogen. We have examined this form of the enzyme by UV-visible, resonance Raman, EPR, and electron nuclear double resonance spectroscopies in conjunction with permutations of 13C- and 15N-labeled cyanide. The results support a model in which one CN- binds through the carbon atom to ferrous a3, supporting a low-spin (S = 0) configuration on the Fe; bridging by this cyanide to the CuB is weak or absent. Four 14N atoms, presumably donated by histidine residues of the protein, provide a strong equatorial ligand field about CuB; a second CN- is coordinated through the carbon atom to CuB in an axial position.

Author List

Surerus KK, Oertling WA, Fan C, Gurbiel RJ, Einarsdóttir O, Antholine WE, Dyer RB, Hoffman BM, Woodruff WH, Fee JA

Author

Kristene K. Surerus in the Chemistry and Biochemistry department at University of Wisconsin - Milwaukee

MESH terms used to index this publication - Major topics in bold

Binding Sites
Copper
Cyanides
Cytochrome b Group
Electron Spin Resonance Spectroscopy
Electron Transport Complex IV
Heme
Iron
Magnetic Resonance Spectroscopy
Nitrogen
Protein Conformation
Spectrophotometry
Spectrum Analysis, Raman
Thermus thermophilus