Cloning and sequence analysis of the gene for phosphoenolpyruvate carboxylase from an extreme thermophile, Thermus sp.

The ppc gene, which encodes phosphoenolpyruvate carboxylase (PEPC) of an extreme thermophile, Thermus sp., was cloned and sequenced. The ppc gene had a high G+C content (69.2%). An open reading frame for a 857-amino-acid polypeptide was found in the gene. The calculated molecular mass was 95,632. The amino acid sequence of Thermus PEPC was 31-37% identical and 52-57% similar to those of 17 PEPCs from mesophilic organisms. No Cys residue was found in the polypeptide, demonstrating that this residue is not essential for the catalytic activity of PEPC. The cloned gene was expressed in Escherichia coli and thermostable PEPC was obtained.