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1859823 
Journal Article 
INFRARED-DETECTABLE GROUPS SENSE CHANGES IN CHARGE-DENSITY ON THE NICKEL CENTER IN HYDROGENASE FROM CHROMATIUM-VINOSUM 
Bagley, KA; Duin, EC; Roseboom, W; Albracht, SPJ; Woodruff, WH 
1995 
Yes 
Biochemistry
ISSN: 0006-2960
EISSN: 1520-4995 
34 
16 
5527-5535 
English 
7727413 
WOS:A1995QV31400026 
Fourier transform infrared studies of nickel hydrogenase from Chromatium vinosum reveal the presence of a set of three absorption bands in the 2100-1900 cm-1 spectral region. These bands, which do not arise from carbon monoxide, have line widths and intensities rivaling those of a band arising from the carbon monoxide stretching frequency (v(CO)) in the Ni(II).CO species of this enzyme [Bagley, K. A., Van Garderen, C. J., Chen, M., Duin, E. C., Albracht, S. P. J., & Woodruff, W. H. (1994) Biochemistry 33, 9229-9236]. The positions of each of these three infrared absorption bands respond in a consistent way to changes in the formal redox state of the nickel center and to the photodissociation of hydrogen bound to the nickel. Up to eight different states of the nickel center have been produced, depending on the redox state and/or the activity state of the enzyme and the presence of carbon monoxide. In seven of these states, the three IR absorption bands in the set have unique frequency positions. It is concluded that the set is due to intrinsic, non-protein groups in the enzyme, whose identities are presently unknown, and that these groups are situated very close to the nickel center and sense the charge density at the Ni site.