Characterization of the relA gene of Porphyromonas gingivalis

Based upon the nucleotide sequence of the relA gene from Escherichia coli, a gene fragment corresponding to the homologous gene from the pathogenic or al bacterium Porphyromonas gingivalis 381 was isolated by PCR and utilized to construct a rel4 mutant. The mutant, KS7, was defective in ribosome-medi ated ppGpp formation and also in the stringent response.