Details
| Original language | English |
|---|---|
| Pages (from-to) | 17251-17257 |
| Number of pages | 7 |
| Journal | Journal of Biological Chemistry |
| Volume | 273 |
| Issue number | 27 |
| Publication status | Published - 3 Jul 1998 |
Abstract
Transport of most nuclear encoded mitochondrial proteins into mitochondria is mediated by heteropolymeric translocases in the membranes of the organelles. The translocase of the outer mitochondrial membrane (TOM) was characterized in fungi, and it was shown that TOM from yeast comprises nine different subunits. This publication is the first report on the preparation of the TOM complex from plant mitochondria. The protein complex from potato was purified by (a) blue native polyacrylamide gel electrophoresis and (b) by immunoaffinity chromatography. On blue native gels, the potato TOM complex runs close to cytochrome c oxidase at 230 kDa and hence only comprises about half of the size of fungal TOM complexes. Analysis of the TOM complex from potato by SDS-polyacrylamide gel electrophoresis allows separation of seven different subunits of 70, 36, 23, 9, 8, 7, and 6 kDa. The 23-kDa protein is identical to the previously characterized potato TOM20 receptor, as shown by in vitro assembly of this protein into the 230kDa complex, by immunoblotting and by direct protein sequencing. Partial amino acid sequence data of the other subunits allowed us to identify sequence similarity between the 36-kDa protein and fungal TOM40. Sequence analysis of cDNAs encoding the 7-kDa protein revealed significant sequence hornology of this protein to TOM7 from yeast. However, potato TOM7 has a N-terminal extension, which is very rich in basic amino acids. Counterparts to the TOM22 and TOM37 proteins from yeast seem to be absent in the potato TOM complex, whereas an additional low molecular mass subunit occurs. Functional implications of these findings are discussed.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Biochemistry
- Biochemistry, Genetics and Molecular Biology(all)
- Molecular Biology
- Biochemistry, Genetics and Molecular Biology(all)
- Cell Biology
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In: Journal of Biological Chemistry, Vol. 273, No. 27, 03.07.1998, p. 17251-17257.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Unique composition of the preprotein translocase of the outer mitochondrial membrane from plants
AU - Jänsch, Lothar
AU - Kruft, Volker
AU - Schmitz, Udo
AU - Braun, Hans-Peter
PY - 1998/7/3
Y1 - 1998/7/3
N2 - Transport of most nuclear encoded mitochondrial proteins into mitochondria is mediated by heteropolymeric translocases in the membranes of the organelles. The translocase of the outer mitochondrial membrane (TOM) was characterized in fungi, and it was shown that TOM from yeast comprises nine different subunits. This publication is the first report on the preparation of the TOM complex from plant mitochondria. The protein complex from potato was purified by (a) blue native polyacrylamide gel electrophoresis and (b) by immunoaffinity chromatography. On blue native gels, the potato TOM complex runs close to cytochrome c oxidase at 230 kDa and hence only comprises about half of the size of fungal TOM complexes. Analysis of the TOM complex from potato by SDS-polyacrylamide gel electrophoresis allows separation of seven different subunits of 70, 36, 23, 9, 8, 7, and 6 kDa. The 23-kDa protein is identical to the previously characterized potato TOM20 receptor, as shown by in vitro assembly of this protein into the 230kDa complex, by immunoblotting and by direct protein sequencing. Partial amino acid sequence data of the other subunits allowed us to identify sequence similarity between the 36-kDa protein and fungal TOM40. Sequence analysis of cDNAs encoding the 7-kDa protein revealed significant sequence hornology of this protein to TOM7 from yeast. However, potato TOM7 has a N-terminal extension, which is very rich in basic amino acids. Counterparts to the TOM22 and TOM37 proteins from yeast seem to be absent in the potato TOM complex, whereas an additional low molecular mass subunit occurs. Functional implications of these findings are discussed.
AB - Transport of most nuclear encoded mitochondrial proteins into mitochondria is mediated by heteropolymeric translocases in the membranes of the organelles. The translocase of the outer mitochondrial membrane (TOM) was characterized in fungi, and it was shown that TOM from yeast comprises nine different subunits. This publication is the first report on the preparation of the TOM complex from plant mitochondria. The protein complex from potato was purified by (a) blue native polyacrylamide gel electrophoresis and (b) by immunoaffinity chromatography. On blue native gels, the potato TOM complex runs close to cytochrome c oxidase at 230 kDa and hence only comprises about half of the size of fungal TOM complexes. Analysis of the TOM complex from potato by SDS-polyacrylamide gel electrophoresis allows separation of seven different subunits of 70, 36, 23, 9, 8, 7, and 6 kDa. The 23-kDa protein is identical to the previously characterized potato TOM20 receptor, as shown by in vitro assembly of this protein into the 230kDa complex, by immunoblotting and by direct protein sequencing. Partial amino acid sequence data of the other subunits allowed us to identify sequence similarity between the 36-kDa protein and fungal TOM40. Sequence analysis of cDNAs encoding the 7-kDa protein revealed significant sequence hornology of this protein to TOM7 from yeast. However, potato TOM7 has a N-terminal extension, which is very rich in basic amino acids. Counterparts to the TOM22 and TOM37 proteins from yeast seem to be absent in the potato TOM complex, whereas an additional low molecular mass subunit occurs. Functional implications of these findings are discussed.
UR - http://www.scopus.com/inward/record.url?scp=0032479295&partnerID=8YFLogxK
U2 - 10.1074/jbc.273.27.17251
DO - 10.1074/jbc.273.27.17251
M3 - Article
C2 - 9642296
AN - SCOPUS:0032479295
VL - 273
SP - 17251
EP - 17257
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 27
ER -