5X0Q

OxyR2 E204G variant (Cl-bound) from Vibrio vulnificus

Summary for 5X0Q

• Entry DOI: 10.2210/pdb5x0q/pdb
• Related: 5B70 5B7D 5X0V
• Descriptor: LysR family transcriptional regulator, CHLORIDE ION, CITRIC ACID, ... (4 entities in total)
• Functional Keywords: lysr-type transcription regulator, lttr, oxyr, h2o2, dna binding protein
• Biological source: Vibrio vulnificus
• Total number of polymer chains: 2
• Total formula weight: 48414.59

Authors

Jo, I.,Ha, N.-C. (deposition date: 2017-01-23, release date: 2017-03-15, Last modification date: 2023-11-22)

Primary citation

Jo, I.,Kim, D.,Bang, Y.-J.,Ahn, J.,Choi, S.H.,Ha, N.-C.
The hydrogen peroxide hypersensitivity of OxyR2 in Vibrio vulnificus depends on conformational constraints
J. Biol. Chem., 292:7223-7232, 2017

PubMed Abstract: Most Gram-negative bacteria respond to excessive levels of HO using the peroxide-sensing transcriptional regulator OxyR, which can induce the expression of antioxidant genes to restore normality. has two distinct OxyRs (OxyR1 and OxyR2), which are sensitive to different levels of HO and induce expression of two different peroxidases, Prx1 and Prx2. Although OxyR1 has both high sequence similarity and HO sensitivity comparable with that of other OxyR proteins, OxyR2 exhibits limited sequence similarity and is more sensitive to HO To investigate the basis for this difference, we determined crystal structures and carried out biochemical analyses of OxyR2. The determined structure of OxyR2 revealed a flipped conformation of the peptide bond before Glu-204, a position occupied by glycine in other OxyR proteins. Activity assays showed that the sensitivity to HO was reduced to the level of other OxyR proteins by the E204G mutation. We solved the structure of the OxyR2-E204G mutant with the same packing environment. The structure of the mutant revealed a dual conformation of the peptide bond before Gly-204, indicating the structural flexibility of the region. This structural duality extended to the backbone atoms of Gly-204 and the imidazole ring of His-205, which interact with HO and invariant water molecules near the peroxidatic cysteine, respectively. Structural comparison suggests that Glu-204 in OxyR2 provides rigidity to the region that is important in HO sensing, compared with the E204G structure or other OxyR proteins. Our findings provide a structural basis for the higher sensitivity of OxyR2 to HO and also suggest a molecular mechanism for bacterial regulation of expression of antioxidant genes at divergent concentrations of cellular HO.

PubMed: 28264933
DOI: 10.1074/jbc.M116.743765

Experimental method

X-RAY DIFFRACTION (1.55 Å)