1H, 13C, and 15N Resonance Assignments of the DNA Binding Domain of MucR from Brucella abortus in Complex with DNA

Abstract

MucR is a conserved global regulator in α-proteobacteria, essential for virulence in Brucella and symbiotic adaptation in rhizobia. It primarily acts as a xenogeneic silencer, repressing AT-rich horizontally acquired genes. Structurally, MucR comprises an N-terminal oligomerization domain, a linker region, and a C-terminal zinc finger DNA-binding domain. Here, we report the optimization of NMR experimental condition and NMR resonance assignments for the complex formed by the C-terminal DNA-binding domain of MucR and 3A3T-DNA. Nearly complete assignments are obtained for ¹H, ¹³C, and ¹⁵N resonances of the protein and ¹H resonances of 3A3T-DNA. Histidine tautomeric state analysis confirms that the two zinc-coordinating histidine residues adopt N^δ1–H tautomeric state. Additional NMR-based analyses provided structural insights into the MucR^CTD and DNA complex formation. The NMR assignments provide a good basis for further structural study of the DNA binding and recognition mechanism of MucR.