Purification, crystallization and preliminary X-ray crystallographic analysis of the C-terminal cytoplasmic domain of FlhB from Aquifex aeolicus

FlhB is a key protein in the regulation of protein export by the bacterial flagellar secretion system. It is composed of two domains: an N‐terminal transmembrane domain and a C‐terminal cytoplasmic domain (FlhBc). Here, the crystallization and preliminary crystallographic analysis of FlhBc from Aquifex aeolicus are reported. Purified protein was crystallized using the vapour‐diffusion technique. The crystals diffracted to 2.3 Å resolution and belonged to space group C2, with unit‐cell parameters a = 114.49, b = 33.89, c = 122.13 Å, β = 107.53°.