The PapC C-terminal domain is a structural domain found at the C-terminus of the E. coli PapC protein. Pili are assembled using the chaperone usher system. In E.coli this is composed of the chaperone PapD and the usher PapC. This domain represents the C-terminal domain from PapC and its homologs. This domain has a beta-sandwich structure similar to the plug domain of PapC.