Premium
Search for novel redox groups in mitochondrial NADH:ubiquinone oxidoreductase (complex I) by diode array UV/VIS spectroscopy
Author(s) -
Schulte Ulrich,
Abelmann Anke,
Amling Natascha,
Brors Benedikt,
Friedrich Thorsten,
Kintscher Lars,
Rasmussen Tim,
Weiss Hanns
Publication year - 1998
Publication title -
biofactors
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 94
eISSN - 1872-8081
pISSN - 0951-6433
DOI - 10.1002/biof.5520080303
Subject(s) - redox , spectroscopy , oxidoreductase , chemistry , photochemistry , biochemistry , physics , inorganic chemistry , enzyme , quantum mechanics
The proton‐translocating NADH:ubiquinone oxidoreductase of mitochondria (complex I) is a large L‐shaped multi‐subunit complex. The peripheral matrix arm contains one FMN and a number of iron‐sulfur (FeS) clusters and is involved in NADH oxidation and electron transfer to the membrane intrinsic arm. There, following a yet unknown mechanism, the redox‐driven proton translocation and the ubiquinone reduction take place. Redox groups that would be able to link electron transfer with proton translocation have not been found so far in the membrane arm. We searched for such groups in complex I isolated from Neurospora crassa. Under anaerobic conditions, the preparation was analyzed in different redox states by means of UV/VIS and EPR spectroscopy. Absorption bands in the UV/VIS redox difference spectra were found which cannot be attributed to the FMN or the EPR detectable FeS clusters. The existence of two novel groups is postulated and their possible locations in the electron pathway and their roles in proton translocation are discussed.