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Asp563 of the horizontal helix of subunit NuoL is involved in proton translocation by the respiratory complex I
Author(s) -
Steimle Stefan,
Willistein Max,
Hegger Patricia,
Janoschke Marco,
Erhardt Heiko,
Friedrich Thorsten
Publication year - 2012
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/j.febslet.2012.01.056
Subject(s) - chromosomal translocation , oxidoreductase , helix (gastropod) , protein subunit , stoichiometry , proton , crystallography , chemistry , biophysics , electron transport chain , stereochemistry , biology , biochemistry , enzyme , physics , gene , ecology , organic chemistry , quantum mechanics , snail
The NADH:ubiquinone oxidoreductase couples the electron transfer from NADH to ubiquinone with the translocation of protons across the membrane. It contains a 110 Å long helix running parallel to the membrane part of the complex. Deletion of the helix resulted in a reduced H + /e − stoichiometry indicating its direct involvement in proton translocation. Here, we show that the mutation of the conserved amino acid D563 L , which is part of the horizontal helix of the Escherichia coli complex I, leads to a reduced H + /e − stoichiometry. It is discussed that this residue is involved in transferring protons to the membranous proton translocation site.