Extended N‐terminal sequencing of proteins of the large ribosomal subunit from yeast mitochondria

Abstract
We have determined the N‐termini of 26 proteins of the large ribosomal subunit from yeast mitochondria by direct amino acid micro‐sequencing. The N‐terminal sequences of proteins YmL33 and YmL38 showed a significant similarity to eubacterial ribosomal (r‐) proteins L30 and L14, respectively. In addition, several proteins could be assigned to their corresponding yeast nuclear genes. Based on a comparison of the protein sequences deduced from the corresponding DNA regions with the N‐termini of the mature proteins, the putative leader peptides responsible for mitochondrial matrix‐targeting were compiled. In most leader sequences a relative abundance of aromatic amino acids, preferentially phenylalanine, was found.