CLONING AND CHARACTERIZATION OF THE GAMMA-GLUTAMYL PHOSPHATE REDUCTASE GENE OF CAMPYLOBACTER-JEJUNI

The gamma-glutamyl phosphate reductase gene, proA, of Campylobacter je juni was isolated from a recombinant pBR322 clone. A HindIII fragment of the insert containing the gene was subcloned into pUC19 and sequenc ed in both orientations. The deduced amino acid sequence of gamma-glut amyl phosphate reductase (EC 1.2.1.41) of C.jejuni exhibits 36.4% iden tity to that of Escherichia coli and 36.0% identity to Serratia marces cens. Two highly conserved regions in the amino acid sequence were ide ntified from the alignment of the three available gamma-glutamyl phosp hate reductase gene sequences. The gene was expressed from its own pro moter and the transcription start site was mapped. The proline biosynt hetic genes of C. jejuni are not located tandemly and thus differ in t his respect from those of E. coli and S. marcescens, where gamma-gluta myl phosphate reductase and gamma-glutamyl kinase (proB) are located i n a single operon.