PDBsum entry 2j3v

Toxin

PDB id: 2j3v

Contents

Protein chain

430 a.a. *

Ligands

GOL ×15

SO4 ×14

Waters ×325

* Residue conservation analysis

PDB id:

2j3v

Name:

Toxin

Title:

Crystal structure of the enzymatic component c2-i of the c2-toxin from clostridium botulinum at ph 3.0

Structure:

C2 toxin component i. Chain: a. Synonym: adp-ribosyltransferase c2-i. Engineered: yes. Mutation: yes

Source:

Clostridium botulinum. Organism_taxid: 1491. Expressed in: escherichia coli. Expression_system_taxid: 511693.

Resolution:

2.11Å R-factor: 0.191 R-free: 0.238

Authors:

C.Schleberger,H.Hochmann,H.Barth,K.Aktories,G.E.Schulz

Key ref:

C.Schleberger et al. (2006). Structure and action of the binary C2 toxin from Clostridium botulinum. J Mol Biol, 364, 705-715. PubMed id: 17027031 DOI: 10.1016/j.jmb.2006.09.002

Date:

23-Aug-06 Release date: 11-Oct-06

Protein chain

O69275  (O69275_CLOBO) -  C2 toxin (Component I) from Clostridium botulinum

Seq: 431 a.a.

Struc: 430 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

DOI no: 10.1016/j.jmb.2006.09.002

J Mol Biol 364:705-715 (2006)

PubMed id: 17027031

Structure and action of the binary C2 toxin from Clostridium botulinum.

C.Schleberger, H.Hochmann, H.Barth, K.Aktories, G.E.Schulz.

ABSTRACT

C2 toxin from Clostridium botulinum is composed of the enzyme component C2-I, which ADP-ribosylates actin, and the binding and translocation component C2-II, responsible for the interaction with eukaryotic cell receptors and the following endocytosis. Three C2-I crystal structures at resolutions of up to 1.75 A are presented together with a crystal structure of C2-II at an appreciably lower resolution and a model of the prepore formed by fragment C2-IIa. The C2-I structure was determined at pH 3.0 and at pH 6.1. The structural differences are small, indicating that C2-I does not unfold, even at a pH value as low as 3.0. The ADP-ribosyl transferase activity of C2-I was determined for alpha and beta/gamma-actin and related to that of Iota toxin and of mutant S361R of C2-I that introduced the arginine observed in Iota toxin. The substantial activity differences between alpha and beta/gamma-actin cannot be explained by the protein structures currently available. The structure of the transport component C2-II at pH 4.3 was established by molecular replacement using a model of the protective antigen of anthrax toxin at pH 6.0. The C-terminal receptor-binding domain of C2-II could not be located but was present in the crystals. It may be mobile. The relative orientation and positions of the four other domains of C2-II do not differ much from those of the protective antigen, indicating that no large conformational changes occur between pH 4.3 and pH 6.0. A model of the C2-IIa prepore structure was constructed based on the corresponding assembly of the protective antigen. It revealed a surprisingly large number of asparagine residues lining the pore. The interaction between C2-I and C2-IIa and the translocation of C2-I into the target cell are discussed.

Selected figure(s)

Figure 3.
Figure 3. Stereoview of C2-I (carrying NAD^+ transferred from IotaA) and β/γ-actin (top, accession code 2BTF) in the proposed reaction geometry. Both models are shown in an inflated-stick-mode and opened by a total angle of 32° towards the viewer so that the contacting surfaces can be visualized. A dotted straight line between the C1′-carbon of NAD^+ and the modified Arg177 of actin indicates the ADP-ribosyl transfer. The three α versus β/γ-actin substitutions on the interaction surface as well as Mut-S361R of C2-I are colored pink and labeled (black).

Figure 6.
Figure 6. Stereoview of a model of the C2-IIa heptamer as derived from a superposition with the established prepore structure of PA[63] from anthrax toxin.^4 (a) Model of the C2-IIa prepore shown in an inflated-stick-mode. The expected docking site of the enzymic component C2-I as derived from experimental data for anthrax toxin is yellow.^19^,^20 (b) Ribbon plot of two adjacent subunits of the C2-IIa model as viewed from the lumen of the prepore. All residues pointing into the prepore lumen are drawn out and numbered. The mobile loop containing Phe428 is labeled. The blue sphere marks position 319, which was suggested to form the tip of the putative α-hemolysin-like β-barrel inserted into the membrane.^4

The above figures are reprinted by permission from Elsevier: J Mol Biol (2006, 364, 705-715) copyright 2006.

Figures were selected by the author.