Figure 1. Schematic overview of PrgB domain organization and function.
(A) Updated schematic overview of the domain organization of PrgB. SS: signal sequence, COI: coiled-coil, PAD: polymer adhesin domain, CSA: adhesin isopeptide-forming adherence domain, CSC: cell-surface antigen C-terminal domain, LPXTG: cell wall anchor sequence. The PrgA cleavage site is located between the polymer adhesin domain and the first immunoglobulin (Ig)-like domain, and has the sequence IFNYGNPKEP. (B) In a setting with a donor cell (green) and multiple recipient cells (brown), PrgB is produced and sits on the cell wall. There it enhances cellular aggregation and/or biofilm formation, either by directly binding lipoteichoic acid (LTA) from the cell wall of a recipient or by binding first to extracellular DNA (eDNA). PrgB compacts the eDNA, and thereby likely pulls the recipient cells closer. Once close enough, PrgB binds to the LTA of the recipient bacteria and facilitates mating-pair formation and conjugation.

