PDBsum entry 2z4i

Signaling protein activator

PDB id: 2z4i

Contents

Protein chains

190 a.a. *

Ligands

P6G

SO4

Waters ×24

* Residue conservation analysis

PDB id:

2z4i

Name:

Signaling protein activator

Title:

Crystal structure of the cpx pathway activator nlpe from escherichia coli

Structure:

Copper homeostasis protein cutf. Chain: a, b. Synonym: lipoprotein nlpe. Engineered: yes. Mutation: yes

Source:

Escherichia coli. Organism_taxid: 562. Gene: nlpe. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.60Å R-factor: 0.224 R-free: 0.270

Authors:

Y.Hirano,M.M.Hossain,K.Takeda,H.Tokuda,K.Miki

Key ref:

Y.Hirano et al. (2007). Structural studies of the Cpx pathway activator NlpE on the outer membrane of Escherichia coli. Structure, 15, 963-976. PubMed id: 17698001 DOI: 10.1016/j.str.2007.06.014

Date:

18-Jun-07 Release date: 04-Sep-07

Protein chains

P40710  (NLPE_ECOLI) -  Lipoprotein NlpE from Escherichia coli (strain K12)

Seq: 236 a.a.

Struc: 190 a.a.

DOI no: 10.1016/j.str.2007.06.014

Structure 15:963-976 (2007)

PubMed id: 17698001

Structural studies of the Cpx pathway activator NlpE on the outer membrane of Escherichia coli.

Y.Hirano, M.M.Hossain, K.Takeda, H.Tokuda, K.Miki.

ABSTRACT

NlpE, an outer membrane lipoprotein, functions during envelope stress responses in Gram-negative bacteria. In Escherichia coli, adhesion to abiotic surfaces has been reported to activate the Cpx pathway in an NlpE-dependent manner. External copper ions are also thought to activate the Cpx pathway mediated by NlpE. We determined the crystal structure of NlpE from E. coli at 2.6 A resolution. The structure showed that NlpE consists of two beta barrel domains. The N-terminal domain resembles the bacterial lipocalin Blc, and the C-terminal domain has an oligonucleotide/oligosaccharide-binding (OB) fold. From both biochemical analyses and the crystal structure, it can be deduced that the cysteine residues in the CXXC motif may be chemically active. Furthermore, two monomers in the asymmetric unit form an unusual 3D domain-swapped dimer. These findings indicate that tertiary and/or quaternary structural instability may be responsible for Cpx pathway activation.

Selected figure(s)

Figure 7.
Figure 7. Structural Properties of the N-Terminal Domain of NlpE
(A) Stereoscopic view of superposition between the N-terminal domain of NlpE (blue) and Blc (magenta, PDB code 1QWD). The rms distance of 68 Cα atoms is 2.2 Å.
(B) The hydrophobic environment of the cavity of the N-terminal β barrel. View from the upside of the cavity. The aromatic residues (Phe, Trp, and Tyr) and the hydrophobic residues (Ala, Cys, Gly, Ile, Leu, Met, Pro, and Val) are colored green and light green, respectively.
(C) The conserved residues of the cavity of the N-terminal β barrel. View from the same direction as in (B). The fully conserved residues are colored red. The strongly conserved residues and the weakly conserved residues are colored dark-orange and light orange, respectively. The fully conserved residues in type I NlpE homologs are colored dark pink (also see Figure 2).

Figure 8.
Figure 8. Structural Properties of the C-Terminal Domain of NlpE
(A) Stereoscopic view of superposition between the C-terminal domain of NlpE (orange) and the N-terminal domain (residues 1–104) of AspRS from E. coli (cyan, PDB code 1C0A). The rms distance of 57 Cα atoms is 1.6 Å.
(B) Surface of the C-terminal domain of NlpE colored red and blue, representing electrostatic potentials from −15 to +15 k[B]T (k[B], the Boltzmann constant; T, the absolute temperature). View from the same orientation as in (C).
(C) Surface of the N-terminal domain of AspRS colored the same as in (B). View from the DNA-binding site.

The above figures are reprinted by permission from Cell Press: Structure (2007, 15, 963-976) copyright 2007.

Figures were selected by an automated process.