Pilin

[3][4] Menningococcal type IV pili bind DNA through the minor pilin ComP via an electropositive stripe that is predicted to be exposed on the filament's surface.

[7] The Saf pilin N-terminal extension protein domain helps the pili to form, via a complex mechanism named the chaperone/usher pathway.

These are virulence factors crucial for cell adhesion to the host and biofilm formation with successful infection.

The structure has been well conserved, as they contain a set of alternating hydrophobic residues that form an essential part of the subunit–subunit interaction.

The N terminus sequences contain a motif of alternating hydrophobic residues that occupy the P2 to P5 binding pockets in the groove of the first pilus subunit.

Recently, the pilin protein from Streptococcus pyogenes has been split into two fragments to develop a new molecular tool called the isopeptag.

This new peptide tag can allow scientists to target and isolate their proteins of interest through a permanent covalent bond.