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A directional electron transfer regulator based on heme‐chain architecture in the small tetraheme cytochrome c from Shewanella oneidensis
Author(s) -
Harada Erisa,
Kumagai Jiro,
Ozawa Kiyoshi,
Imabayashi Shinichiro,
Tsapin Alexandre S,
Nealson Kenneth H,
Meyer Terrance E,
Cusanovich Michael A,
Akutsu Hideo
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)03696-7
Subject(s) - shewanella oneidensis , heme , chemistry , cytochrome , redox , electron transfer , cytochrome c , biophysics , electron transport chain , stereochemistry , biochemistry , photochemistry , mitochondrion , biology , bacteria , enzyme , inorganic chemistry , genetics
The macroscopic and microscopic redox potentials of the four hemes of the small tetraheme cytochrome c from Shewanella oneidensis were determined. The microscopic redox potentials show that the order of reduction is from hemes in the C‐terminal domain (hemes 3 and 4) to the N‐terminal domain (heme 1), demonstrating the polarization of the tetraheme chain during reduction. This makes heme 4 the most efficient electron delivery site. Furthermore, multi‐step reduction of other redox centers through either heme 4 or heme 3 is shown to be possible. This has provided new insights into the two‐electron reduction of the flavin in the homologous flavocytochrome c –fumarate reductase.