PDBsum entry 4l6t

Hydrolase

PDB id: 4l6t

Contents

Protein chains

249 a.a.

105 a.a.

Ligands

BGC-GAL-NGA-GAL-SIA ×5

Metals

_ZN

Waters ×563

PDB id:

4l6t

Name:

Hydrolase

Title:

Gm1 bound form of the ecx ab5 holotoxin

Structure:

Ecxa. Chain: a. Engineered: yes. Ecxb. Chain: b, c, d, e, f. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 562. Strain: 176. Gene: ecxa. Expressed in: escherichia coli. Expression_system_taxid: 469008. Gene: ecxb.

Resolution:

1.86Å R-factor: 0.179 R-free: 0.198

Authors:

D.R.Littler,N.M.Ng,J.Rossjohn,T.Beddoe

Key ref:

N.M.Ng et al. (2013). EcxAB is a founding member of a new family of metalloprotease AB5 toxins with a hybrid cholera-like B subunit. Structure, 21, 2003-2013. PubMed id: 24095060 DOI: 10.1016/j.str.2013.08.024

Date:

12-Jun-13 Release date: 06-Nov-13

Protein chain

Q8GAV4  (Q8GAV4_ECOLX) -  ECXA from Escherichia coli

Seq: 285 a.a.

Struc: 249 a.a.

Protein chains

Q8GAV3  (Q8GAV3_ECOLX) -  ECXB from Escherichia coli

Seq: 125 a.a.

Struc: 105 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: Chain A: E.C.3.4.24.- - ?????

DOI no: 10.1016/j.str.2013.08.024

Structure 21:2003-2013 (2013)

PubMed id: 24095060

EcxAB is a founding member of a new family of metalloprotease AB5 toxins with a hybrid cholera-like B subunit.

N.M.Ng, D.R.Littler, A.W.Paton, J.Le Nours, J.Rossjohn, J.C.Paton, T.Beddoe.

ABSTRACT

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.