6lxl

From Proteopedia

Crystal structure of C-terminal DNA-binding domain of Escherichia coli OmpR

Structural highlights

6lxl is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 3.56Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

OMPR_ECOLI The N-terminus of this protein is required for the transcriptional expression of both major outer membrane protein genes ompF and ompC; its C-terminal moiety mediates the multimerization of the OmpR protein. As a multimer, it turns on the expression of the ompC gene; as a monomer, it turns on the expression of the ompF gene.

Publication Abstract from PubMed

OmpR, a response regulator of the EnvZ/OmpR two-component system (TCS), controls the reciprocal regulation of two porin proteins, OmpF and OmpC, in bacteria. During signal transduction, OmpR (OmpR-FL) undergoes phosphorylation at its conserved Asp residue in the N-terminal receiver domain (OmpRn) and recognizes the promoter DNA from its C-terminal DNA-binding domain (OmpRc) to elicit an adaptive response. Apart from that, OmpR regulates many genes in Escherichia coli and is important for virulence in several pathogens. However, the molecular mechanism of the regulation and the structural basis of OmpR-DNA binding is still not fully clear. In this study, we presented the crystal structure of OmpRc in complex with the F1 region of the ompF promoter DNA from E. coli. Our structural analysis suggested that OmpRc binds to its cognate DNA as a homodimer, only in a head-to-tail orientation. Also, the OmpRc apo-form showed a unique domain-swapped crystal structure under different crystallization conditions. Biophysical experimental data, such as NMR, fluorescent polarization and thermal stability, showed that inactive OmpR-FL (unphosphorylated) could bind to promoter DNA with a weaker binding affinity as compared with active OmpR-FL (phosphorylated) or OmpRc, and also confirmed that phosphorylation may only enhance DNA binding. Furthermore, the dimerization interfaces in the OmpRc-DNA complex structure identified in this study provide an opportunity to understand the regulatory role of OmpR and explore the potential for this "druggable" target.

Structural basis for promoter DNA recognition by the response regulator OmpR.,Sadotra S, Lou YC, Tang HC, Chiu YC, Hsu CH, Chen C J Struct Biol. 2020 Nov 3;213(1):107638. doi: 10.1016/j.jsb.2020.107638. PMID:33152421^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Sadotra S, Lou YC, Tang HC, Chiu YC, Hsu CH, Chen C. Structural basis for promoter DNA recognition by the response regulator OmpR. J Struct Biol. 2020 Nov 3;213(1):107638. doi: 10.1016/j.jsb.2020.107638. PMID:33152421 doi:http://dx.doi.org/10.1016/j.jsb.2020.107638