Molecular cloning of a Chinese hamster mitochondrial protein related to the 'chaperonin' family of bacterial and plant proteins

D. J. Picketts, C. S K Mayanil, R. S. Gupta

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The complete cDNA sequence of a mitochondrial protein from Chinese hamster ovary cells, designated P1, which was originally identified as a microtubule-related protein (Gupta, R.S., Ho, T.K.W., Moffat, M.R.K., and Gupta, R. (1982) J. Biol. Chem. 257, 1071-1078), has been determined. The P1 cDNA encodes a protein of 60,983 Da including a 26-amino acid putative mitochondrial targeting sequence at its N-terminal end. The deduced amino acid sequence of Chinese hamster P1 shows 97% identity to the human P1 protein. Most interestingly, the amino acid sequences of mammalian P1 proteins show extensive sequence homology (42-60% identical residues and an additional 15-25% conservative replacements) to the 'chaperonin' family of bacterial, yeast, and plant proteins (viz. groEL protein of Escherichia coli, hsp 60 protein of yeast, and ribulose-1,5-bisphosphate carboxylase subunit binding protein of plant chloroplasts) and to the 60-65-kDa major antigenic protein of mycobacteria and Coxiella burnetii. The homology between mammalian P1 and other proteins begins after the putative mitochondrial presequence and extends up to the C-terminal end. Furthermore, similar to the chaperonin family of proteins, P1 appears to exist in cells as a homooligomeric complex of seven subunits and shows ATPase activity. These observations strongly indicate that P1 protein is a member of the chaperonin family and that it may be involved in a similar function in mammalian cells.

Original languageEnglish (US)
Pages (from-to)12001-12008
Number of pages8
JournalJournal of Biological Chemistry
Issue number20
StatePublished - 1989

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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