Characterization of the paramagnetic iron‐containing redox centres of Thiosphaera pantotropha periplasmic nitrate reductase

FEBS Letters

Ferguson, Stuart J.²  Reilly, Ann¹  Berks, Ben C.¹  Richardson, David J.¹  Breton, Jacques¹  Thomson, Andrew J.¹ 

[1] Centre for Metalloprotein Spectroscopy and Biology, Schools of Biological and Chemical Sciences, University of East Anglia, Norwich, NR4 7TJ, UK;Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK

关键词: Periplasmic nitrate reductase;    Iron—sulphur protein;    cytochrome c-type;    Thiosphaera pantotropha;    EPR;    electron paramagnetic resonance;    MGD;    molybdopterin guanine dinucleotide;   

DOI  :  10.1016/0014-5793(94)00445-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Electron paramagnetic resonance spectroscopy signals attributable to low-spin haem c in the oxidised protein and [4Fe–4S]¹⁺ in the dithionite-reduced protein were identified, at low temperature, in Thiosphaera pantotropha periplasmic nitrate reductase. Spin integration of these signals as well as elemental analysis suggest a stoichiometry of 1.3–1.6 c-haem and 1 [4Fe–4S] cluster per enzyme molecule. The E _m (at pH 7.4) of the [4F–4S]^2+,1+ couple, −160 mV, means that it is unlikely to be physiologically reducible. Peptide sequences from the 90 kDa subunit indicate that the enzyme is a member of the family of molybdopterin guanine dinucleotide-binding polypeptides, the majority of which possess a putative [4Fe–4S] cluster binding sequence and thus may also bind a (low potential) iron—sulphur cluster.

【 授权许可】

Unknown