ISSN:
1432-1017
Keywords:
Key words Cytochrome c′′
;
Ligand orientation
;
Methylophilus methylotrophus
;
13C NMR
;
Heme electronic structure
;
Fermi contact shift
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract Cytochrome c′′ from Methylophilus methylotrophus contains a single haem with bis-histidine coordination which couples electron and proton transfer by reversible detachment of one of the axial ligands on reduction. 13C NMR of the haem substituents is now used to determine the orientations of the two histidine ligands of the ferricytochrome. The relative orientation of the ligands is found to be nearly perpendicular (an angle of 85±2° between the histidine planes was obtained), which is consistent with the near-axial g-tensor determined by EPR. Although the absolute orientation of the axial ligands is not well defined in the presence of near-axial symmetry, 13C NMR is found to be a useful complement to EPR for obtaining quantitative information for systems of this type.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002490050011
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