3QZC

Structure of the periplasmic stress response protein CpxP

Summary for 3QZC

• Entry DOI: 10.2210/pdb3qzc/pdb
• Descriptor: Periplasmic protein CpxP, ZINC ION (3 entities in total)
• Functional Keywords: alpha-helical hairpin, ltxxq motif, stress response regulator, signaling protein
• Biological source: Escherichia coli
• Cellular location: Periplasm : P0AE85
• Total number of polymer chains: 2
• Total formula weight: 28129.60

Authors

Thede, G.L.,Edwards, R.A.,Glover, J.N.M. (deposition date: 2011-03-04, release date: 2011-03-23, Last modification date: 2024-02-21)

Primary citation

Thede, G.L.,Arthur, D.C.,Edwards, R.A.,Buelow, D.R.,Wong, J.L.,Raivio, T.L.,Glover, J.N.
Structure of the Periplasmic Stress Response Protein CpxP.
J.Bacteriol., 193:2149-2157, 2011

PubMed Abstract: CpxP is a novel bacterial periplasmic protein with no homologues of known function. In gram-negative enteric bacteria, CpxP is thought to interact with the two-component sensor kinase, CpxA, to inhibit induction of the Cpx envelope stress response in the absence of protein misfolding. CpxP has also been shown to facilitate DegP-mediated proteolysis of misfolded proteins. Six mutations that negate the ability of CpxP to function as a signaling protein are localized in or near two conserved LTXXQ motifs that define a class of proteins with similarity to CpxP, Pfam PF07813. To gain insight into how these mutations might affect CpxP signaling and/or proteolytic adaptor functions, the crystal structure of CpxP from Escherichia coli was determined to 2.85-Å resolution. The structure revealed an antiparallel dimer of intertwined α-helices with a highly basic concave surface. Each protomer consists of a long, hooked and bent hairpin fold, with the conserved LTXXQ motifs forming two diverging turns at one end. Biochemical studies demonstrated that CpxP maintains a dimeric state but may undergo a slight structural adjustment in response to the inducing cue, alkaline pH. Three of the six previously characterized cpxP loss-of-function mutations, M59T, Q55P, and Q128H, likely result from a destabilization of the protein fold, whereas the R60Q, D61E, and D61V mutations may alter intermolecular interactions.

PubMed: 21317318
DOI: 10.1128/JB.01296-10

Experimental method

X-RAY DIFFRACTION (2.85 Å)