Molecular structure of the 8.0 kDa subunit of cytochrome-c reductase from potato and its Δψ-dependent import into isolated mitochondria

authored by: Hans Peter Braun, Udo K. Schmitz
Abstract: The cytochrome-c reductase (EC 1.10.2.2) of the mitochondrial respiratory chain couples electron transport from ubiquinol to cytochrome c with proton translocation across the inner mitochondrial membrane. The enzyme from potato was shown to be composed of 10 subunits. Isolation and characterization of cDNA clones for the second smallest subunit reveal an open reading frame of 216 bp encoding a protein of 8.0 kDa. The protein exhibits similarities to a 7.2/7.3 kDa subunit of cytochrome-c reductase from bovine and yeast, that is localized on the intermembrane space side of the enzyme complex. It also shows similarity to a previously unidentified 7.8 kDa protein of cytochrome-c reductase from Euglena. The potato 8.0 kDa protein has a segmental structure, as its sequence can be devided into four parts, each comprising a central Arg-(Xaa)₅-Val motif. N-terminal sequencing of the mature 8.0 kDa protein indicates the absence of a cleavable mitochondrial targeting sequence. Import of the in vitro synthesized 8.0 kDa protein into isolated potato mitochondria confirms the lack of a presequence and reveals a dependence of the transport on the membrane potatial Δψ across the inner mitochondrial membrane. These features are unique among the intermembrane space proteins known so far.
External Organisation(s): Max Planck Institute of Molecular Plant Physiology (MPI-MP)
Type: Article
Journal: BBA - Bioenergetics
Volume: 1229
Pages: 181-186
No. of pages: 6
ISSN: 0005-2728
Publication date: 26.04.1995
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Biophysics, Biochemistry, Cell Biology
Electronic version(s): https://doi.org/10.1016/0005-2728(94)00199-F (Access: Open)

BibTeX

@article{e5faa72b7bd14b52afea961d7fa9df10,
title = "Molecular structure of the 8.0 kDa subunit of cytochrome-c reductase from potato and its Δψ-dependent import into isolated mitochondria",
abstract = "The cytochrome-c reductase (EC 1.10.2.2) of the mitochondrial respiratory chain couples electron transport from ubiquinol to cytochrome c with proton translocation across the inner mitochondrial membrane. The enzyme from potato was shown to be composed of 10 subunits. Isolation and characterization of cDNA clones for the second smallest subunit reveal an open reading frame of 216 bp encoding a protein of 8.0 kDa. The protein exhibits similarities to a 7.2/7.3 kDa subunit of cytochrome-c reductase from bovine and yeast, that is localized on the intermembrane space side of the enzyme complex. It also shows similarity to a previously unidentified 7.8 kDa protein of cytochrome-c reductase from Euglena. The potato 8.0 kDa protein has a segmental structure, as its sequence can be devided into four parts, each comprising a central Arg-(Xaa)5-Val motif. N-terminal sequencing of the mature 8.0 kDa protein indicates the absence of a cleavable mitochondrial targeting sequence. Import of the in vitro synthesized 8.0 kDa protein into isolated potato mitochondria confirms the lack of a presequence and reveals a dependence of the transport on the membrane potatial Δψ across the inner mitochondrial membrane. These features are unique among the intermembrane space proteins known so far.",
keywords = "(S. tuberosum), bc complex, Cytochrome-c reductase, Mitochondrion, Protein transport, Respiratory chain",
author = "Braun, {Hans Peter} and Schmitz, {Udo K.}",
note = "Funding information: We wish to thank Dr. V. Kruft for the determination of the N-terminal sequence of the potato 8.0 kDa protein and H. Mentzel for excellent technical assistance. This work was supported by the Deutsche Forschungsgemeinschaft, grant Schm. 698/2 and by the BMFT.",
year = "1995",
month = apr,
day = "26",
doi = "10.1016/0005-2728(94)00199-F",
language = "English",
volume = "1229",
pages = "181--186",
journal = "BBA - Bioenergetics",
issn = "0005-2728",
publisher = "Elsevier",
number = "2",
}