FEBS Letters | |
On the two iron centers of desulfoferrodoxin | |
Hagen, Wilfred R.1  Verhagen, Marc F.J.M.1  Wolbert, Ronnie B.G.1  Kolkman, Joost A.1  Voorhorst, Wilfried G.B.1  | |
[1] Department of Biochemistry, Agricultural University, Dreijenlaan 3, NL-6703 HA Wageningen, The Netherlands | |
关键词: Bioelectrochemistry; EPR; Rubredoxin; Redox; Desulfovibrio vulgaris (H); | |
DOI : 10.1016/0014-5793(93)81599-U | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Desulfoferrodoxin from Desulfovibrio vulgaris, strain Hildenborough, is a homodimer of 28 kDa; it contains two Fe atoms per 14.0 kDa subunit. The N-terminal amino-acid sequence is homogeneous and corresponds to the previously described Rbo gene, which encodes a highly charged 14 kDa polypeptide without a leader sequence. Although one of the two iron centers, FeA, has previously been described as a ‘strained rubredoxin-like’ site, EPR of the ferric form proves very similar to that of the pentagonal bipyramidally coordinated iron in ferric complexes of DTPA, diethylenetriaminepentaacetic acid: both systems have spin S = and rhombicity E/D = 0.08. Unlike the Fe site in rubredoxin the FeA site in desulfoferrodoxin has a pH dependent midpoint potential with pK ox= 9.2 and pK red = 5.3. Upon reduction (E m,7.5 = +2 mV) FeA exhibits an unusually sharp S = 2 resonance in parallel-mode EPR. The second iron, FeB, has S = and E/D = 0.33; upon reduction (E m,7.5 = +90 mV) FeB turns EPR-silent.
【 授权许可】
Unknown
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