The pili are polar flexible filaments of about 5.4 nanometers diameter and 2.5 micrometers average length; they consist of only a single polypeptide chain arranged in a helical configuration of five subunits per turn in the assembled pilus. Moraxella bovis can express either a Q or a I pilin, the inversion of 2 kb of DNA determines which pilin is expressed. Belongs to the N-Me-Phe pilin family. In PubMed:2902184 it is said that 50% of the peptides have N-methyl-Phe and 50% begin with Thr-8. N-terminal methylation produces preview during Edman degradation, which makes this appear to happen when the peptide is completely N-terminally methylated.