Subunit 1 of cytochrome oxidase from Neurospora crassa: nucleotide sequence of the coding gene and partial amino acid sequence of the protein

Abstract

A partial protein sequence (223 residues) of cytochrome oxidase subunit 1 from Neurospora crassa has been established. The nucleotide sequence of a cloned mitochondrial DNA segment, including the structural gene coding for the mature subunit 1 (CO I locus) was determined. In contrast to the situation in yeast, the CO I locus in N. crassa is not interrupted by long intervening sequences. A polypeptide of 555 residues with a mol. wt. of 61 000 has been deduced from the reading frame established by protein sequencing. With the exception of the C-terminal part of the polypeptide, the proposed sequences for subunit 1 of N. crassa, yeast, and man are largely homologous. Protein sequencing reveals that a region of low homology close to the C-terminal portion belongs to the structural gene in N. crassa. The DNA sequence coding for the prepiece , which characterizes the polypeptide precursor of the N. crassa subunit 1, has not yet been localized. A RNA species of approximately 6.8 kb has been identified as the CO I transcript. There is no indication of splicing of this large transcript.