Fig. 3.

Schematic illustration of Sortase-mediated pili. A) Pilus assembly which consist of tip pilin (red), Shaft (green) and the base (brown). B. 1) The pilin precursors synthezised from the cytosol enters through the sec machinery. 2) The pilin- specific sortase SrtC (yellow) recognizes the tip pilin and cleaves at the sorting motif and forms an acyl sortase complex. The pilus specific sortase receives a nucleophilic attack from the lysine side chain from the backbone pilin to form a covalent bond between the pilins and undergoes pilin polymerization. C) The housekeeping sortase undergoes a nucleophilic attack from lipid II molecule. 4) The polymerized pilin is further anchored to the cell wall. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)