Detection of the mitochondrially encoded cytochrome c oxidase subunit I in the trypanosomatid protozoan Leishmania tarentolae. Evidence for translation of unedited mRNA in the kinetoplast.
With the aim of identification of kinetoplast-encoded proteins we investigated the subunit composition of cytochrome c oxidase (respiratory complex IV) from kinetoplast mitochondria of the trypanosomatid protozoan Leishmania tarentolae. Eleven stoichiometric subunits were visible in Coomassie-stained, two-dimensional Blue Native/Tricine-SDS electrophoretic gels. Their partial amino acid sequences indicated that these polypeptides are nuclear-encoded. The mitochondrial subunit I was detected with the polyclonal antibodies against an internal region of this polypeptide. In two-dimensional (9 versus 14%) polyacrylamide glycine-SDS gels this subunit is found as a series of spots located off the main diagonal, a property that can be explained by abnormal electrophoretic migration and aggregation. In gels loaded with high amounts of the purified, enzymatically active oxidase, the subunit I spots could be visualized by staining. The determined N-terminal amino acid sequence of the putative monomeric subunit I (MFXLCLVCLSVS) matched with the predicted sequence, thus indicating that the corresponding kinetoplast unedited mRNA is translated into a functional protein.
Horvath
A
A
Department of Biology and the Department of Entomology, University of California, Riverside, California 92521, USA.
Kingan
T G
TG
Maslov
D A
DA
D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D007891:Leishmania / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D017393:RNA Editing; D012333:RNA, Messenger / Q000235:genetics*
D012333:RNA, Messenger; D003576:Electron Transport Complex IV