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A stable intermediate product of the archaeal zinc‐containing 7Fe ferredoxin from Sulfolobus sp. strain 7 by artificial oxidative conversion
Author(s) -
Iwasaki Toshio,
Oshima Tairo
Publication year - 1997
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(97)01286-6
Subject(s) - ferredoxin , zinc , chemistry , strain (injury) , biochemistry , biology , organic chemistry , enzyme , anatomy
Irreversible conversion of the purified zinc‐containing 7Fe ferredoxin from the thermoacidophilic archaeon Sulfolobus sp. strain 7 was found to occur under aerobic conditions at pH 5.0 and at 4°C. This process accompanied a substantial increase of the electron paramagnetic resonance signal attributed to a [3Fe‐4S] 1+ cluster, and the converted form containing ∼6 Fe/Zn (mol/mol) had a net charge different from that of the native 7Fe ferredoxin. These data provide evidence for the formation of a stable intermediate product of the archaeal ferredoxin having two [3Fe‐4S] clusters and a zinc center by artificial oxidative degradation. This further explains the discrepancy that a zinc center and two [3Fe‐4S] clusters (but not a zinc center and one [3Fe‐4S] cluster plus one [4Fe‐4S] cluster) are observed in the crystal structure at pH 5.0.