ABSTRACT
The phosphoenolpyruvate (PEP) carboxykinase-encoding gene from the anaerobic, CO2-fixing, succinate-producing bacterium Anaerobiospirillum succiniciproducens was cloned, sequenced, and expressed in Escherichia coli. The gene encoded a 532-residue polypeptide with a calculated molecular mass of 58.7 kDa. The sequence of the A. succiniciproducens PEP carboxykinase was similar to those of all known ATP/ADP-dependent PEP carboxykinases. In particular, the A. succiniciproducens enzyme was 67.3% identical and 79.2% similar to the E. coli enzyme. The A. succiniciproducens pckA transcription start site was determined, and putative promoter regions were identified. The recombinant enzyme was overexpressed in E. coli. The purified enzyme was indiscernible from the native enzyme by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had the same activity as the native enzyme.
