The oxidized subunit B8 from human complex I adopts a thioredoxin fold.
Subunit B8 from ubiquinone oxidoreductase (complex I) (CI-B8) is one of several nuclear-encoded supernumerary subunits that are not present in bacterial complex I. Its solution structure shows a thioredoxin fold with highest similarities to the human thioredoxin mutant C73S and thioredoxin 2 from Anabeana sp. Interestingly, these proteins contain active sites in the same area, where the disulfide bond of oxidized CI-B8 is located. The redox potential of this disulfide bond is -251.6 mV, comparing well to that of disulfides in other thioredoxin-like proteins. Analysis of the structure reveals a surface area that is exclusively composed of highly conserved residues and thus most likely a subunit interaction site within complex I.
Brockmann
Christoph
C
Forschungsinstitut für Molekulare Pharmakologie, D-13125 Berlin, Germany.
Diehl
Annette
A
Rehbein
Kristina
K
Strauss
Holger
H
Schmieder
Peter
P
Korn
Bernhard
B
Kühne
Ronald
R
Oschkinat
Hartmut
H
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D004220:Disulfides / Q000737:chemistry; D042967:Electron Transport Complex I / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010084:Oxidation-Reduction; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013879:Thioredoxins / Q000737:chemistry* / Q000235:genetics
D004220:Disulfides; D021122:Protein Subunits; D013879:Thioredoxins; D042967:Electron Transport Complex I