Major component of the type IV fimbriae that plays an essential role in twitching motility, natural transformation, and protease secretion. 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. The sequence shown is that of isolate 340. Belongs to the N-Me-Phe pilin family.