Structural Studies of the Carbon Monoxide Complex of [NiFe]hydrogenase from Desulfovibrio vulgaris Miyazaki F: Suggestion for the Initial Activation Site for Dihydrogen
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- 作者：Hideaki Ogata ; Yasutaka Mizoguchi ; Nobuhiro Mizuno ; Kunio Miki ; Shin-ichi Adachi ; Noritake Yasuoka ; Tatsuhiko Yagi ; Osamu Yamauchi ; Shun Hirota ; and Yoshiki Higuchi
- 刊名：Journal of the American Chemical Society
- 出版年：2002
- 出版时间：October 2, 2002
- 年：2002
- 卷：124
- 期：39
- 页码：11628 - 11635
- 全文大小：277K
- 年卷期：v.124,no.39(October 2, 2002)
- ISSN：1520-5126
文摘
The carbon monoxide complex of [NiFe]hydrogenase from Desulfovibrio vulgaris Miyazaki Fhas been characterized by X-ray crystallography and absorption and resonance Raman spectroscopy.Nine crystal structures of the [NiFe]hydrogenase in the CO-bound and CO-liberated forms were determinedat 1.2-1.4 Å resolution. The exogenously added CO was assigned to be bound to the Ni atom at theNi-Fe active site. The CO was not replaced with H2 in the dark at 100 K, but was liberated by illuminationwith a strong white light. The Ni-C distances and Ni-C-O angles were about 1.77 Å and 160
, respectively,except for one case (1.72 Å and 135), in which an additional electron density peak between the CO andS
(Cys546) was recognized. Distinct changes were observed in the electron density distribution of the Niand S(Cys546) atoms between the CO-bound and CO-liberated structures for all the crystals tested. Thenovel structural features found near the Ni and S(Cys546) atoms suggest that these two atoms at theNi-Fe active site play a role during the initial H2-binding process. Anaerobic addition of CO to dithionite-reduced [NiFe]hydrogenase led to a new absorption band at about 470 nm (~3000 M-1cm-1). ResonanceRaman spectra (excitation at 476.5 nm) of the CO complex revealed CO-isotope-sensitive bands at 375/393 and 430 cm-1 (368 and 413 cm-1 for 13C18O). The frequencies and relative intensities of the CO-related Raman bands indicated that the exogenous CO is bound to the Ni atom with a bent Ni-C-Ostructure in solution, in agreement with the refined structure determined by X-ray crystallography.
, respectively,except for one case (1.72 Å and 135), in which an additional electron density peak between the CO andS(Cys546) was recognized. Distinct changes were observed in the electron density distribution of the Niand S(Cys546) atoms between the CO-bound and CO-liberated structures for all the crystals tested. Thenovel structural features found near the Ni and S(Cys546) atoms suggest that these two atoms at theNi-Fe active site play a role during the initial H2-binding process. Anaerobic addition of CO to dithionite-reduced [NiFe]hydrogenase led to a new absorption band at about 470 nm (~3000 M-1cm-1). ResonanceRaman spectra (excitation at 476.5 nm) of the CO complex revealed CO-isotope-sensitive bands at 375/393 and 430 cm-1 (368 and 413 cm-1 for 13C18O). The frequencies and relative intensities of the CO-related Raman bands indicated that the exogenous CO is bound to the Ni atom with a bent Ni-C-Ostructure in solution, in agreement with the refined structure determined by X-ray crystallography.