7F9I

The apo-form structure of EnrR

Summary for 7F9I

• Entry DOI: 10.2210/pdb7f9i/pdb
• Descriptor: EnrR repressor (2 entities in total)
• Functional Keywords: enrr, repressor, dna binding, dna binding protein
• Biological source: Edwardsiella piscicida
• Total number of polymer chains: 2
• Total formula weight: 20461.23

Authors

Gan, J.H.,Wang, Q.Y. (deposition date: 2021-07-04, release date: 2022-05-11, Last modification date: 2023-11-29)

Primary citation

Ma, R.,Liu, Y.,Gan, J.,Qiao, H.,Ma, J.,Zhang, Y.,Bu, Y.,Shao, S.,Zhang, Y.,Wang, Q.
Xenogeneic nucleoid-associated EnrR thwarts H-NS silencing of bacterial virulence with unique DNA binding.
Nucleic Acids Res., 50:3777-3798, 2022

PubMed Abstract: Type III and type VI secretion systems (T3/T6SS) are encoded in horizontally acquired genomic islands (GIs) that play crucial roles in evolution and virulence in bacterial pathogens. T3/T6SS expression is subjected to tight control by the host xenogeneic silencer H-NS, but how this mechanism is counteracted remains to be illuminated. Here, we report that xenogeneic nucleoid-associated protein EnrR encoded in a GI is essential for virulence in pathogenic bacteria Edwardsiella and Salmonella. We showed that EnrR plays critical roles in T3/T6SS expression in these bacteria. Various biochemical and genetic analyses demonstrated that EnrR binds and derepresses the promoter of esrB, the critical regulator of T3/T6SS, to promote their expression by competing with H-NS. Additionally, EnrR targets AT-rich regions, globally modulates the expression of ∼363 genes and is involved in various cellular processes. Crystal structures of EnrR in complex with a specific AT-rich palindromic DNA revealed a new DNA-binding mode that involves conserved HTH-mediated interactions with the major groove and contacts of its N-terminal extension to the minor groove in the symmetry-related duplex. Collectively, these data demonstrate that EnrR is a virulence activator that can antagonize H-NS, highlighting a unique mechanism by which bacterial xenogeneic regulators recognize and regulate foreign DNA.

PubMed: 35325196
DOI: 10.1093/nar/gkac180

Experimental method

X-RAY DIFFRACTION (2.5 Å)