To understand the operator specificity of HigA2, its structure in complex with a 17 bp blunt end operator fragment was determined by X-ray crystallography (Supplementary Table 1 ). We have previously shown that HigA2 is a dimer in solution 22 , 23 . In the structure with the operator, HigA2 binds to the DNA also as a dimer and induces a 33° bend in the DNA molecule. (Fig. 1c ). Only the globular C-terminal HigA2 domain, corresponding to the residues 37-104, could be observed; the N-terminal IDR ...