PDBsum entry 4pl0

Transport protein

PDB id: 4pl0

Contents

Protein chains

571 a.a.

Ligands

ANP ×2

BNG ×2

Metals

_MG ×2

PDB id:

4pl0

Name:

Transport protein

Title:

Crystal structure of the antibacterial peptide abc transporter mcjd in an outward occluded state

Structure:

Microcin-j25 export atp-binding/permease protein mcjd. Chain: a, b. Synonym: microcin-j25 immunity protein,microcin-j25 secretion atp- binding protein mcjd. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 562. Gene: mcjd. Expressed in: escherichia coli k-12. Expression_system_taxid: 83333.

Resolution:

2.70Å R-factor: 0.248 R-free: 0.266

Authors:

H.G.Choudhury,K.Beis

Key ref:

H.G.Choudhury et al. (2014). Structure of an antibacterial peptide ATP-binding cassette transporter in a novel outward occluded state. Proc Natl Acad Sci U S A, 111, 9145-9150. PubMed id: 24920594 DOI: 10.1073/pnas.1320506111

Date:

15-May-14 Release date: 18-Jun-14

Protein chains

Q9X2W0  (MCJD_ECOLX) -  Microcin-J25 export ATP-binding/permease protein McjD from Escherichia coli

Seq: 580 a.a.

Struc: 571 a.a.

DOI no: 10.1073/pnas.1320506111

Proc Natl Acad Sci U S A 111:9145-9150 (2014)

PubMed id: 24920594

Structure of an antibacterial peptide ATP-binding cassette transporter in a novel outward occluded state.

H.G.Choudhury, Z.Tong, I.Mathavan, Y.Li, S.Iwata, S.Zirah, S.Rebuffat, H.W.van Veen, K.Beis.

ABSTRACT

Enterobacteriaceae produce antimicrobial peptides for survival under nutrient starvation. Microcin J25 (MccJ25) is an antimicrobial peptide with a unique lasso topology. It is secreted by the ATP-binding cassette (ABC) exporter McjD, which ensures self-immunity of the producing strain through efficient export of the toxic mature peptide from the cell. Here we have determined the crystal structure of McjD from Escherichia coli at 2.7-Å resolution, which is to the authors' knowledge the first structure of an antibacterial peptide ABC transporter. Our functional and biochemical analyses demonstrate McjD-dependent immunity to MccJ25 through efflux of the peptide. McjD can directly bind MccJ25 and displays a basal ATPase activity that is stimulated by MccJ25 in both detergent solution and proteoliposomes. McjD adopts a new conformation, termed nucleotide-bound outward occluded. The new conformation defines a clear cavity; mutagenesis and ligand binding studies of the cavity have identified Phe86, Asn134, and Asn302 as important for recognition of MccJ25. Comparisons with the inward-open MsbA and outward-open Sav1866 structures show that McjD has structural similarities with both states without the intertwining of transmembrane (TM) helices. The occluded state is formed by rotation of TMs 1 and 2 toward the equivalent TMs of the opposite monomer, unlike Sav1866 where they intertwine with TMs 3-6 of the opposite monomer. Cysteine cross-linking studies on the McjD dimer in inside-out membrane vesicles of E. coli confirmed the presence of the occluded state. We therefore propose that the outward-occluded state represents a transition intermediate between the outward-open and inward-open conformation of ABC exporters.