THE COMPLETE PRIMARY STRUCTURE OF RAT CHAPERONIN-10 REVEALS A PUTATIVE-BETA-ALPHA-BETA NUCLEOTIDE-BINDING DOMAIN WITH HOMOLOGY TO P21(RAS)

The first complete amino-acid sequence of a mitochondrial chaperonin 1 0 is reported. The amino-terminal alanine residue is acetylated, a mod ification that may be required for the interaction with heptameric cha peronin 60. Part of the sequence constitutes a potential dinucleotide binding motif and is identical with 7 out of 10 residues in the GTP-bi nding site of p21ras. This similarity may be the structural basis for the recently discovered complex between p21ras and chaperonin 60 in in tact cells (Ikawa, S. and Weinberg, R.A. (1992) Proc. Natl. Acad. Sci. USA 89, 2012-2016).