Purification and sequencing of cytochrome b from potato reveals methionine cleavage of a mitochondrially encoded protein.
Several mitochondrial genes from a large number of different fungi, mammals and plants have been sequenced but little is known about the corresponding translation products. We have affinity purified cytochrome c reductase from potato mitochondria and isolated the mitochondrially encoded cytochrome b protein. Amino-terminal sequencing reveals that the polypeptide does not start with a methionine. Comparison of the amino acid sequence with the recently published sequence of the gene encoding the cytochrome b apoprotein suggests that the N-formylmethionine is removed. This result provides the first evidence for the presence of a deformylase and a methionine aminopeptidase in mitochondria.
Braun
H P
HP
Institut für Genbiologische Forschung Berlin GmbH, Berlin, Germany.
Schmitz
U K
UK
D000595:Amino Acid Sequence; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D003573:Cytochrome b Group / Q000737:chemistry / Q000302:isolation & purification*; D004272:DNA, Mitochondrial; D008715:Methionine / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D011198:Solanum tuberosum / Q000201:enzymology*
D003573:Cytochrome b Group; D004272:DNA, Mitochondrial; D008715:Methionine