TYPE-IV PREPILIN PEPTIDASE GENE OF NEISSERIA-GONORRHOEAE MS11 - PRESENCE OF A RELATED GENE IN OTHER PILIATED AND NONPILIATED NEISSERIA STRAINS

The assembly of type IV pili in Neisseria gonorrhoeae is a complex process likely to require the products of many genes. One of these is the enzyme prepilin peptidase, which cleaves and then N methylates the precursor pilin subunits prior to their assembly into pill. We have used a PCR amplification strategy to clone the N. gonorrhoeae prepilin peptidase gene, pilD(Ng). A single copy of the gene is shown to be present in the chromosome. Its product promotes correct cleavage of the gonococcal prepilin in Escherichia coli cells carrying both the prepilin peptidase gene and the pilin structural gene. PilD(Ng) also cleaves prePulG, a type N pilin-like protein of Krebsiella oxytoca, Moreover, PilD(Ng) complements a mutation in the gene coding for the prepilin peptidase-like protein of K. oxytoca, pulO, partially restoring PulG-PulO-dependent extracellular secretion of the enzyme pullulanase. Finally, we show that genes homologous to pilD(Ng) are present and expressed in a variety of species in the genus Neisseria, including some commensal strains.