Objective AphB is a key transcriptional regulator of Vibrio cholerae that can activate the expression of virulence genes.The aims of this study were to obtain crystals of the C-terminal of AphB protein and to investigate the role of AphB in the regulation of transcription. Methods The AphB gene was cloned into the prokaryotic expression vector pET-32a(+)and AphB protein was overexpressed in E.coli.The protein was purified using Ni+affinity chromatography,MonoQ anion-exchange chromatography,and GF75 gel filt...