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

Abstract

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 ¹H, ¹³C and ¹⁵N 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.