This entry includes Flagellar hook-associated protein 1 (FlgK or HAP1), one of three HAPs that form the hook-filament junction and has structural similarity to flagellin. FlgK is required for normal flagellum assembly. Proteins in this entry have a multidomain fold comprising an elongated alpha-helical scaffold core, and depending on the bacterial species, a variable number of smaller domains [1]. This entry represents a beta-sandwich domain from FlgK proteins; Salmonella typhimurium FlgK (Swiss:P0A1J5) has one beta-sandwich domain, while FlgK from Burkholderia pseudomallei has two of them protruding from the alpha-helical core, referred to as D2 and D3 domains in [1], of which the first one, D2, is covered in this entry [1]. FlgK has cytotoxic effects suggesting an important role in pathogenesis and is highly immunogenic. Domains D2 and D3 from B. pseudomallei have been identified as epitopes with increased immunogenic potential for vaccine development.

1: From crystal structure to in silico epitope discovery in the Burkholderia pseudomallei flagellar hook-associated protein FlgK. Gourlay LJ, Thomas RJ, Peri C, Conchillo-Sole O, Ferrer-Navarro M, Nithichanon A, Vila J, Daura X, Lertmemongkolchai G, Titball R, Colombo G, Bolognesi M; FEBS J. 2015;282:1319-1333. PMID:25645451