Crystallization and X-ray crystallographic analysis of the C-terminal domain of Bacillus subtilis GabR in complex with pyridoxal 5 -phosphate and γ-aminobutyric acid

Bacillus subtilis GabR (BsGabR) functions as a transcriptional activator that regulates the expression of gabTD operon involved in the γ-aminobutyric acid (GABA) catabolism. Most studies of BsGabR have been focused on the structurefunctional relationship regarding the Cterminal aminotransferase-like domain of BsGabR (BsGabR-CTD), but it still remains unclear due to lack of the structural information containing the GABA. To better understand the role of this domain, BsGabR-CTD was purified and crystallized in complex with pyridoxal 5 -phosphate and GABA. The crystal of ternary complex diffracted to a resolution of 2.0 Å and belonged to the tetragonal space group P41, with unit-cell parameters a = b = 118.497, c = 75.862 Å. Preliminary molecular replacement further confirmed the presence of one dimer in the asymmetric with a Matthews coefficient (VM) of 2.86 Å3 Da-1, corresponding to a solvent content of 56.9%.