4L63 image
Deposition Date 2013-06-11
Release Date 2013-11-27
Last Version Date 2024-11-06
Entry Detail
PDB ID:
4L63
Keywords:
Title:
Apo form of AB5 holotoxin
Biological Source:
Source Organism:
Escherichia coli (Taxon ID: 562)
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.80 Å
R-Value Free:
0.19
R-Value Work:
0.17
R-Value Observed:
0.17
Space Group:
P 65 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:ECXA
Gene (Uniprot):ecxA
Chain IDs:A
Chain Length:266
Number of Molecules:1
Biological Source:Escherichia coli
Polymer Type:polypeptide(L)
Molecule:ECXB
Gene (Uniprot):ecxB
Chain IDs:B, C, D, E, F
Chain Length:112
Number of Molecules:5
Biological Source:Escherichia coli
Primary Citation
EcxAB Is a Founding Member of a New Family of Metalloprotease AB5 Toxins with a Hybrid Cholera-like B Subunit.
Structure 21 2003 2013 (2013)
PMID: 24095060 DOI: 10.1016/j.str.2013.08.024

Abstact

AB5 toxins are composed of an enzymatic A subunit that disrupts cellular function associated with a pentameric B subunit required for host cell invasion. EcxAB is an AB5 toxin isolated from clinical strains of Escherichia coli classified as part of the cholera family due to B subunit homology. Cholera-group toxins have catalytic ADP-ribosyltransferases as their A subunits, so it was surprising that EcxA did not. We confirmed that EcxAB self-associates as a functional toxin and obtained its structure. EcxAB is a prototypical member of a hybrid AB5 toxin family containing metzincin-type metalloproteases as their active A subunit paired to a cholera-like B subunit. Furthermore, EcxA is distinct from previously characterized proteases and thus founds an AB5-associated metzincin family that we term the toxilysins. EcxAB provides the first observation of conserved B subunit usage across different AB5 toxin families and provides evidence that the intersubunit interface of these toxins is far more permissive than previously supposed.

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