Backbone resonance assignment of the catalytic and ATP-binding domain of CpxA from Escherichia coli

CpxA is an extensively studied histidine kinase implicated in cellular stress responses. The highly conserved CA domain of CpxA (CpxA(CA)) is an essential domain for the hydrolysis of ATP and the binding of inhibitors and considered to be a promising target for broad-spectrum antimicrobial drugs development. The ATP-binding pocket in the CA domain contains a flexible ATP lid motif. Although the crystal structure of CA domain has been defined, the structure of the ATP lid remains uncertain, posing a challenge to the study of its catalytic mechanism. In this study, we report the backbone H-1, C-13 and N-15 chemical shift assignments of CpxA(CA) by heteronuclear multidimensional spectroscopy and predict its secondary structure in solution using TALOS(+). The residues of ATP lid motif are well-assigned. Therefore, this study provides a foundation for understanding the role of CpxA(CA) in cellular signaling and the development of novel antimicrobial therapies.