FT-IR Characterization of the Light-Induced Ni-L2 and Ni-L3 States of [NiFe] Hydrogenase from Desulfovibrio vulgaris Miyazaki F

• DOI: 10.1021/acs.jpcb.5b03075
• Publication Date: 2015-04-21T18:52:40Z
• Authors: Hulin Tai; Koji Nishikawa; Seiya Inoue; Yoshiki Higuchi; Shun Hirota
• Keywords: Hydrogenase; Desulfovibrio vulgaris; Oxidation state

Different light-induced Ni-L states of [NiFe] hydrogenase from its Ni-C state have previously been observed by EPR spectroscopy. Herein, we succeeded in detecting simultaneously two Desulfovibrio vulgaris Miyazaki F FT-IR A new νCO band at 1890 cm–1 and νCN bands 2034 2047 were detected the spectra H2-activated enzyme under N2 atmosphere basic conditions, addition to 1910 2061 Ni-L2 state. The attributed Ni-L3 comparison spectra. frequencies are lowest among corresponding standard-type hydrogenases various redox states. These results indicate that a residue, presumably Ni-coordinating Cys546, is protonated deprotonated states, respectively. Relatively small ΔH (6.4 ± 0.8 kJ mol–1) ΔS (25.5 10.3 J mol–1 K–1) values obtained for conversion state, which was agreement with previous proposals deprotonation Cys546 important catalytic reaction enzyme.