Ni l-edge soft x-ray spectroscopy of ni-fe hydrogenases and modelcompounds--evidence for high-spin ni(ii) in the active enzyme

Journal Article · Wed Mar 15 04:00:00 EST 2000 · Journal of the American Chemical Society

OSTI ID:908156

Wang, Hongxin; Ralston, C Y; Patil, D S; Jones, R M; Gu, M; Verhagen, M; Adams, M; Ge, P; Riordan, C; Marganian, C A; Mascharak, P; Kovacs, J; Miller, C G; Collins, T J; Brooker, S; Croucher, P D; Wang, Kun; Stiefel, E I; Cramer, S P

L-edge X-ray absorption spectroscopy has been used to study, under a variety of conditions, the electronic structure of Ni in the Ni-Fe hydrogenases from Desulfovibrio gigas, Desulfovibrio baculatus, and Pyrococcus furiosus. The status of the enzyme films used for these measurements was monitored by FT-IR spectroscopy. The L-edge spectra were interpreted by ligand field multiplet simulations and by comparison with data for Ni model complexes. The spectrum for Ni in D. gigas enzyme ''form A'' is consistent with a covalent Ni(III) species. In contrast, all of the reduced enzyme samples exhibited high spin Ni(II) spectra. The significance of the Ni(II) spin state for the structure of the hydrogenase active site is discussed.

• Research Organization: COLLABORATION - UCDavis
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 908156
• Report Number(s): LBNL--46609
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Vol. 121; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ENZYMES
HYDROGENASES
X-RAY SPECTROSCOPY