Isolation and characterization of the gene encoding an aminopeptidase involved in the selective toxicity of ascamycin toward Xanthomonas campestris pv. citri

摘要

pAn aminopeptidase gene named iXAP/i has been isolated from iXanthomonas campestris/i pv. icitri/i, a plant pathogenic bacterium. The bacterium is one of the rare micro-organisms susceptible to ascamycin, an aminoacyl nucleoside antibiotic that inhibits protein synthesis. Sequence analysis reveals that the gene encodes a 311 amino acid protein with a calculated molecular mass of 35134 Da and approx. 50% identity for amino acids to the proline iminopeptidase from iNeisseria gonorrhoeae/i. The iXAP/i gene product, Xap, expressed in iEscherichia coli/i has proline iminopeptidase activity as well as ascamycin dealanylating activity iin vitro/i./p