CLONING AND EXPRESSION OF THE INORGANIC PYROPHOSPHATASE GENE FROM THERMOPHILIC BACTERIUM PS-3

The thermophilic bacterium PS-3 ppa gene encoding inorganic pyrophosph atase (PPiase) has been cloned and sequenced. The deduced amino acid s equence was exactly the same as that determined on Edman degradation ( Ichiba, T., Takenaka, O., Samejima, T. and Hachimori, A., J. Biochem. 108: 572-578, 1990) except that amino acid-70 is threonine instead of proline and two more amino acids, Asn-Lys, are present at the carboxyl terminus. The structural gene containing BamH I and Hind III restrict ion cleaving sites at the 5' and 3' ends, respectively, was amplified by the PCR method. Escherichia coli JM109 was transformed with a synth etic DNA, and we found that thermophilic ppa was expressed in E. coli, as judged on enzyme assaying, SDS-PAGE and immune assaying.