Crystal structure of an inactive variant of the quorum-sensing master regulator HapR from the protease-deficient non-O1, non-O139 Vibrio cholerae strain V2.
Cruite, J., Succo, P., Raychaudhuri, S., Kull, F.J.(2018) Acta Crystallogr F Struct Biol Commun 74: 331-336
- PubMed: 29870016 
- DOI: https://doi.org/10.1107/S2053230X18006519
- Primary Citation of Related Structures:  
6D7R - PubMed Abstract: 
HapR is a TetR-family transcriptional regulator that controls quorum sensing in Vibrio cholerae, the causative agent of cholera. HapR regulates the expression of hemagglutinin protease, virulence and biofilm genes. The crystal structure of wild-type HapR from V. cholerae strain O1 El Tor C6706 has previously been solved. In this study, the structure of a DNA-binding-deficient variant of HapR (HapR V2 ) derived from the protease-deficient V. cholerae serotype O37 strain V2 is reported. The structure reveals no structural differences compared with wild-type HapR. However, structural alignment of HapR V2 with the TetR-family member QacR in complex with its operator DNA suggests that the aspartate residue located between the regulatory and DNA-binding domains may clash with and electrostatically repel the phosphate backbone of DNA to prevent binding.
Organizational Affiliation: 
Department of Biochemistry, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA.