Asp563 of the horizontal helix of subunit NuoL is involved in proton translocation by the respiratory complex I.
The NADH:ubiquinone oxidoreductase couples the electron transfer from NADH to ubiquinone with the translocation of protons across the membrane. It contains a 110Å 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.
Albert-Ludwigs-Universität Freiburg, Institut für Organische Chemie und Biochemie, Freiburg i. Br., Germany.
Stefan
S
Steimle
Max
M
Willistein
Patricia
P
Hegger
Marco
M
Janoschke
Heiko
H
Erhardt
Thorsten
T
Friedrich
D000595:Amino Acid Sequence; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism*; D004579:Electron Transport; D042967:Electron Transport Complex I / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009245:NADH Dehydrogenase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D011522:Protons; D016415:Sequence Alignment
D029968:Escherichia coli Proteins; D011522:Protons; D001224:Aspartic Acid; D009245:NADH Dehydrogenase; C479743:NuoL protein, E coli; D042967:Electron Transport Complex I