ChapFlgA is a family similar to the SAF family, and includes chaperones for flagellar basal-body proteins and pilus-assembly proteins, FlgA, RcpB and CpaB. ChapFlgA is necessary for the formation of the P-ring of the flagellum, FlgI, which sits in the peptidoglycan layer of the outer membrane of the bacterium. FlgA plays an auxiliary role in P-ring assembly [1,2].

1: The Salmonella FlgA protein, a putativeve periplasmic chaperone essential for flagellar P ring formation. Nambu T, Kutsukake K; Microbiology. 2000;146:1171-1178. PMID:10832645

2: Coordinating assembly of a bacterial macromolecular machine. Chevance FF, Hughes KT; Nat Rev Microbiol. 2008;6:455-465. PMID:18483484