The type 4 pilin of Moraxella nonliquefaciens exhibits unique similarities with the pilins of Neisseria gonorrhoeae and Dichelobacter (Bacteroides) nodosus.

Moraxella nonliquefaciens is a bacterium which is part of the normal flora of the human upper respiratory tract and is an occasional cause of disease. Using a previously cloned type 4 pilin gene (tfpQ) from Moraxella bovis as a hybridization probe, we have cloned an 826 bp Sau3 AI fragment which contains an M. nonliquefaciens type 4 pilin gene (tfpA) from strain NCTC 7784. The pilin gene is expressed in Escherichia coli. We have examined NCTC 7784 and nine other M. nonliquefaciens strains by genomic Southern hybridization using tfpA as a probe, and they all appeared to have more than one pilin gene. While the predicted amino acid sequence of the M. nonliquefaciens tfpA pilin has conserved regions as compared to pilins of M. bovis and M. lacunata, it also shows similarities to both the type 4 pilin of Neisseria gonorrhoeae and the type 4 pilin of Dichelobacter nodosus (formerly Bacteroides nodosus).