Sequence analysis and complementation studies of the argJ gene encoding ornithine acetyltransferase from Neisseria gonorrhoeae

Abstract

Clinical isolates of Neisseria gonorrhoeae frequently are deficient in arginine biosynthesis. These auxotrophs often have defects in the fifth step of the arginine biosynthetic pathway, the conversion of acetylornithine to ornithine. This reaction is catalyzed by the enzyme ornithine acetyltransferase, which is a product of the argJ gene. We have cloned and sequenced the gonococcal argJ gene and found that it contains an open reading frame of 1,218 nucleotides and encodes a peptide with a deduced Mr of 42,879. This predicted size was supported by minicell analysis. This gene was capable of complementing both Escherichia coli argE and argA mutations and of transforming an ArgJ- strain of N. gonorrhoeae to Arg+. Southern blots were able to detect bands that specifically hybridized to the gonococcal argJ gene in genomic DNA from Pseudomonas aeruginosa but not E. coli, a result that reflects the divergent nature of the arginine biosynthetic pathway in these organisms.