کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1274605 | 972621 | 2011 | 7 صفحه PDF | دانلود رایگان |
The redox behaviour of a ferredoxin (Fd) from Desulfovibrio alaskensis was characterized by electrochemistry. The protein was isolated and purified, and showed to be a tetramer containing one [3Fe–4S] and one [4Fe–4S] centre. This ferredoxin has high homology with FdI from Desulfovibrio vulgaris Miyazaki and Hildenborough and FdIII from Desulfovibrio africanus.From differential pulse voltammetry the following signals were identified: [3Fe-4S]+ 1/0 (E0′ = − 158 ± 5 mV); [4Fe–4S]+ 2/+1 (E0′ = − 474 ± 5 mV) and [3Fe–4S]0/− 2 (E0′ = − 660 ± 5 mV). The effect of pH on these signals showed that the reduced [3Fe–4S]0 cluster has a pKʹred′ = 5.1 ± 0.1, the [4Fe–4S]+ 2/+1 centre is pH independent, and the [3Fe–4S]0/−2 reduction is accompanied by the binding of two protons. The ability of the [3Fe–4S]0 cluster to be converted into a new [4Fe–4S] cluster was proven. The redox potential of the original [4Fe–4S] centre showed to be dependent on the formation of the new [4Fe-4S] centre, which results in a positive shift (ca. 70 mV) of the redox potential of the original centre.Being most [Fe–S] proteins involved in electron transport processes, the electrochemical characterization of their clusters is essential to understand their biological function. Complementary EPR studies were performed.
Graphical AbstractFigure optionsDownload as PowerPoint slideResearch Highlights
► D. alaskensis Fd is a 7Fe protein containing one [3Fe–4S] and one [4Fe–4S] cluster.
► The [3Fe–4S]0 cluster can be converted into a new [4Fe–4S] cluster.
► E0ʹ of the original [4Fe–4S] centre depends on the formation of the new 4Fe centre.
Journal: Bioelectrochemistry - Volume 82, Issue 1, August 2011, Pages 22–28