Subunit composition of mitochondrial complex I from the yeast Yarrowia lipolytica.
Here we present a first assessment of the subunit inventory of mitochondrial complex I from the obligate aerobic yeast Yarrowia lipolytica. A total of 37 subunits were identified. In addition to the seven central, nuclear coded, and the seven mitochondrially coded subunits, 23 accessory subunits were found based on 2D electrophoretic and mass spectroscopic analysis in combination with sequence information from the Y. lipolytica genome. Nineteen of the 23 accessory subunits are clearly conserved between Y. lipolytica and mammals. The remaining four accessory subunits include NUWM, which has no apparent homologue in any other organism and is predicted to contain a single transmembrane domain bounded by highly charged extramembraneous domains. This structural organization is shared among a group of 7 subunits in the Y. lipolytica and 14 subunits in the mammalian enzyme. Because only five of these subunits display significant evolutionary conservation, their as yet unknown function is proposed to be structure- rather than sequence-specific. The NUWM subunit could be assigned to a hydrophobic subcomplex obtained by fragmentation and sucrose gradient centrifugation. Its position within the membrane arm was determined by electron microscopic single particle analysis of Y. lipolytica complex I decorated with a NUWM-specific monoclonal antibody.
Fachbereich Medizin, Institut für Biochemie I, ZBC, Universität Frankfurt, Theodor-Stern-Kai 7, Haus 25B, D-60590 Frankfurt am Main, Germany.
Albina
A
Abdrakhmanova
Volker
V
Zickermann
Mihnea
M
Bostina
Michael
M
Radermacher
Hermann
H
Schägger
Stefan
S
Kerscher
Ulrich
U
Brandt
D000595:Amino Acid Sequence; D001483:Base Sequence; D042967:Electron Transport Complex I / Q000737:chemistry* / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D008928:Mitochondria / Q000201:enzymology*; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D021122:Protein Subunits / Q000032:analysis* / Q000235:genetics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D025062:Yarrowia / Q000201:enzymology* / Q000235:genetics
D024101:Mitochondrial Proteins; D021122:Protein Subunits; D042967:Electron Transport Complex I