Magnetic circular dichroism of DCPIP‐oxidised Desulfovibrio vulgaris hydrogenase

FEBS Letters

Devlin, F.²  LeGall, J.¹  McKenna, M.C.²  Stephens, P.J.²  Morgan, T.V.²  Czechowski, M.¹  Peck, H.D.¹  DerVartanian, D.V.¹ 

[1]Department of Biochemistry, University of Georgia, Athens, GA 30602, USA

[2]Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0482, USA

关键词: Magnetic circular dichroism;    2;    6-Dichlorophenolindophenol;    Desulfovibrio gigas;    Hydrogenase;   

DOI  :  10.1016/0014-5793(85)80223-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Ni-free hydrogenases commonly exhibit a g_av > 2 EPR spectrum in their most oxidised level. This spectrum has been linked with the active site and generally attributed to an oxidised HIPIP-type, [4Fe-4S]³⁺ cluster. We report the low temperature magnetic circular dichroism (MCD) spectrum of 2,6-dichlorophenolindo-phenol (DCPIP)-oxidised Desulfovibrio vulgaris hydrogenase (DvH₂ase), which exhibits an axial g_av > 2 EPR spectrum. Paramagnetic MCD is observed, which however is shown to arise from an EPR-silent, para-magnetic species with S > . No evidence of paramagnetic MCD arising from the g_av > 2 EPR-detectable species is obtained. We conclude that: (1) DCPIP-oxidised DvH₂ase does not contain either a [4Fe-4S]³⁺ or an oxidised 3Fe cluster; (ii) an EPR-silent species with MCD characteristics somewhat similar to those of the oxidised ‘P’ clusters of the dye-oxidized iron-molybdenum protein of nitrogenase is present in DCPIP-oxidised DvH₂ase; (iii) the MCD and EPR of the g_av > 2 species exhibit characteristics in common with those of the g_av > 2 species produced by Fe(CN)₆ ³⁻ oxidation of the [4Fe-4S]²⁺ cluster of the 7Fe ferredoxin I of Azotobacter vinelandii [(7Fe)FdI). We suggest that the g_av > 2 EPR signal of this and other hydrogenases arises from a species chemically analogous to that observed in (7Fe)FdI.

【 授权许可】

Unknown