Mitochondrial inner membrane protease 1 of Saccharomyces cerevisiae shows sequence similarity to the Escherichia coli leader peptidase.
The nuclear yeast mutant pet ts2858 is defective in the removal of pre-sequences from the mitochondrially encoded cytochrome oxidase subunit II (COXII) and the processing intermediate of cytochrome b2 (Cytb2), a nuclear gene product. In order to identify the genetic lesion in this mutant we have cloned and characterized a DNA region which complements the pet ts2858 mutation. The DNA sequence revealed three open reading frames, one of which is responsible for the complementation. A 570 bp reading frame represents the structural gene PET2858, as demonstrated by in vitro mutagenesis, gene expression from a foreign promoter, and allelism tests. PET2858 encodes a 21.4 kDa protein, which is essential for growth on non-fermentable carbon sources and for the proteolytic processing of COXII and the Cytb2 intermediate. When the N-terminus of the PET2858 protein is fused to a reporter protein, the resulting hybrid molecule is imported into mitochondria. Interestingly, the N-terminal half of the deduced PET2858 protein exhibits 30.7% amino acid identity to the leader peptidase of Escherichia coli. These results suggest that PET2858 codes for a mitochondrial inner membrane protease (IMP1) or at least a subunit of it. This protease is involved in protein processing and export from the mitochondrial matrix.
Behrens
M
M
Botanisches Institut, Universität Düsseldorf, Federal Republic of Germany.
Michaelis
G
G
Pratje
E
E
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D008565:Membrane Proteins / Q000235:genetics*; D008928:Mitochondria / Q000737:chemistry*; D008969:Molecular Sequence Data; D010957:Plasmids; D016364:Reading Frames / Q000235:genetics; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D012697:Serine Endopeptidases; D014170:Transformation, Genetic
D008565:Membrane Proteins; D010450:Endopeptidases; D012697:Serine Endopeptidases; C026515:type I signal peptidase