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Pyrococcus furiosus glyceraldehyde 3‐phosphate oxidoreductase has comparable W 6+/5+ and W 5+/4+ reduction potentials and unusual [4Fe‐4S] EPR properties
Author(s) -
Hagedoorn Peter L,
Freije J.Robert,
Hagen Wilfred R
Publication year - 1999
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(99)01511-2
Subject(s) - pyrococcus furiosus , electron paramagnetic resonance , chemistry , cubane , oxidoreductase , ferredoxin , crystallography , electron transfer , redox , redox titration , stereochemistry , inorganic chemistry , nuclear magnetic resonance , crystal structure , biochemistry , archaea , physics , enzyme , gene
Pyrococcus furiosus glyceraldehyde 3‐phosphate oxidoreductase has been characterized using EPR‐monitored redox titrations. Two different W signals were found. W 1 5+ is an intermediate species in the catalytic cycle, with the midpoint potentials E m (W 6+/5+ )=−507 mV and E m (W 5+/4+ )=−491 mV. W 2 5+ represents an inactivated species with E m (W 6+/5+ )=−329 mV. The cubane cluster exhibits both S=3/2 and S=1/2 signals with the same midpoint potential: E m ([4Fe‐4S] 2+/1+ )=−335 mV. The S=1/2 EPR signal is unusual with all g values below 2.0. The titration results combined with catalytic voltammetry data are consistent with electron transfer from glyceraldehyde 3‐phosphate first to the tungsten center, then to the cubane cluster and finally to the ferredoxin.