A proteomics approach to the identification of mammalian mitochondrial small subunit ribosomal proteins

J Biol Chem. 2000 Oct 20;275(42):32585-91. doi: 10.1074/jbc.M003596200.


Mammalian mitochondrial small subunit ribosomal proteins were separated by two-dimensional polyacrylamide gel electrophoresis. The proteins in six individual spots were subjected to in-gel tryptic digestion. Peptides were separated by capillary liquid chromatography, and the sequences of selected peptides were obtained by electrospray tandem mass spectrometry. The peptide sequences obtained were used to screen human expressed sequence tag data bases, and complete consensus cDNAs were assembled. Mammalian mitochondrial small subunit ribosomal proteins from six different classes of ribosomal proteins were identified. Only two of these proteins have significant sequence similarities to ribosomal proteins from prokaryotes. These proteins correspond to Escherichia coli S10 and S14. Homologs of two human mitochondrial proteins not found in prokaryotes were observed in the genomes of Drosophila melanogaster and Caenorhabditis elegans. A homolog of one of these proteins was observed in D. melanogaster but not in C. elegans, while a homolog of the other was present in C. elegans but not in D. melanogaster. A homolog of one of the ribosomal proteins not found in prokaryotes was tentatively identified in the yeast genome. This latter protein is the first reported example of a ribosomal protein that is shared by mitochondrial ribosomes from lower and higher eukaryotes that does not have a homolog in prokaryotes.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Caenorhabditis elegans
  • Chromatography, Liquid
  • Consensus Sequence
  • DNA, Complementary
  • Drosophila
  • Drosophila Proteins*
  • Escherichia coli / metabolism
  • Humans
  • Mammals
  • Mice
  • Mitochondria / metabolism*
  • Molecular Sequence Data
  • Peptide Fragments / chemistry
  • Peptide Fragments / isolation & purification
  • Proteome / chemistry*
  • Proteome / genetics
  • Proteome / isolation & purification
  • Ribosomal Proteins / chemistry*
  • Ribosomal Proteins / genetics
  • Ribosomal Proteins / isolation & purification
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins*
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Trypsin


  • DNA, Complementary
  • Drosophila Proteins
  • Peptide Fragments
  • Proteome
  • RPS21A protein, S cerevisiae
  • RPS25 protein, human
  • RPS26 protein, human
  • RPS26A protein, S cerevisiae
  • Ribosomal Proteins
  • RpS26 protein, Drosophila
  • Saccharomyces cerevisiae Proteins
  • Trypsin

Associated data

  • GENBANK/P82649
  • GENBANK/P82650
  • GENBANK/P82663
  • GENBANK/P82664
  • GENBANK/P82665
  • GENBANK/P82666
  • GENBANK/P82667
  • GENBANK/P82668
  • GENBANK/P82669
  • GENBANK/P82670