Preparation and preliminary X‐ray diffraction analysis of crystals of bacterial flagellar sigma factor σ28 in complex with the σ28‐binding region of its antisigma factor, FlgM

The sigma 28 kDa (σ28) factor is a transcription factor specific for the expression of bacterial flagellar and chemotaxis genes. Its antisigma factor, FlgM, binds σ28 factor and inhibits its activity as a transcription factor. In this study, crystals of the complex between Escherichia coli σ28 and the C-terminal σ28-binding region of FlgM were obtained. The crystals belong to space group P3121 or P3221, with unit-cell parameters a = b = 106.7 (2), c = 51.74 (3) A, containing one complex in the crystallographic asymmetric unit. An X-ray intensity data set was collected to a resolution of 2.7 A.