A pulsed EPR study of redox‐dependent hyperfine interactions for the nickel centre of Desulfovibrio gigas hydrogenase

FEBS Letters

Peisach, Jack²  Hatchikian, Claude E.¹  Chapman, Alan³  Cammack, Richard³  McCracken, John² 

[1] Laboratoire de Chimie Bacterienne, CNRS BP71, 13277 Marseille, Cédex 9, France;Department of Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA;Department of Biochemistry, King's College, Campden Hill, London W8 7AH, England

关键词: Hydrogenase;    EPR spectroscopy;    Electron spin echo envelope modulation;    Nickel;    Hyperfine interaction;    ESEEM;    electron spin echo envelope modulation;    EPR;    electron paramagnetic resonance;    shf;    superhyperfine;    nqi;    nuclear quadrupolar interaction;   

DOI  :  10.1016/0014-5793(88)81001-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The nickel centre of hydrogenase from Desulfovibrio gigas was studied by electron spin echo envelope modulation (ESEEM) spectroscopy in the oxidized, unready (Ni-A) and H₂-reduced active (Ni-C) states, both in H₂O and ²H₂O solution. Fourier transforms of the 3-pulse ESEEM, taken at 8.7 GHz, for Ni-A and Ni-C in H₂O contained similar peaks with narrow linewidths at frequencies of 0.4, 1.2 and 1.6 MHz, and a broader peak centred at 4.5 MHz. At 11.6 GHz, the low frequency components showed small field-dependent shifts, while the high frequency component was shifted to 5.1 MHz. These results are consistent with the presence of ¹⁴N, possibly from imidazole, coupled to the nickel centre. In ²H₂O, Ni-A was shown to be inaccessible for exchange with solvent deuterons. In contrast, Ni-C was accessible to solvent exchange, with a deuterium population being in close proximity to the metal ion. Thus, the nickel environment of the active protein is different from that in the oxidized or unready state. On illumination of Ni-C, although EPR changes are seen, ¹⁴N coupling remains, and for the ²H₂O sample, deuterium coupling is also retained.

【 授权许可】

Unknown