PDBsum entry 2wn7

Transferase

PDB id: 2wn7

Contents

Protein chain

392 a.a. *

Ligands

NAD

GOL

Waters ×156

* Residue conservation analysis

PDB id:

2wn7

Name:

Transferase

Title:

Structural basis for substrate recognition in the enzymatic component of adp-ribosyltransferase toxin cdta from clostridium difficile

Structure:

Adp-ribosyltransferase enzymatic component. Chain: a. Synonym: actin-ribosylating toxin, cdta. Engineered: yes

Source:

Clostridium difficile. Organism_taxid: 1496. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.25Å R-factor: 0.208 R-free: 0.265

Authors:

A.Sundriyal,A.K.Roberts,C.C.Shone,K.R.Acharya

Key ref:

A.Sundriyal et al. (2009). Structural basis for substrate recognition in the enzymatic component of ADP-ribosyltransferase toxin CDTa from Clostridium difficile. J Biol Chem, 284, 28713-28719. PubMed id: 19692332 DOI: 10.1074/jbc.M109.043018

Date:

07-Jul-09 Release date: 18-Aug-09

Protein chain

Q9KH42  (Q9KH42_CLODI) -  ADP-ribosyltransferase enzymatic component from Clostridioides difficile

Seq: 463 a.a.

Struc: 392 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1074/jbc.M109.043018

J Biol Chem 284:28713-28719 (2009)

PubMed id: 19692332

Structural basis for substrate recognition in the enzymatic component of ADP-ribosyltransferase toxin CDTa from Clostridium difficile.

A.Sundriyal, A.K.Roberts, C.C.Shone, K.R.Acharya.

ABSTRACT

ADP-ribosylation is one of the favored modes of cell intoxication employed by several bacteria. Clostridium difficile is recognized to be an important nosocomial pathogen associated with considerable morbidity and attributable mortality. Along with its two well known toxins, Toxin A and Toxin B, it produces an ADP-ribosylating toxin that targets monomeric actin of the target cell. Like other Clostridial actin ADP-ribosylating toxins, this binary toxin, known as C. difficile toxin (CDT), is composed of two subunits, CDTa and CDTb. In this study, we present high resolution crystal structures of CDTa in its native form (at pH 4.0, 8.5, and 9.0) and in complex with ADP-ribose donors, NAD and NADPH (at pH 9.0). The crystal structures of the native protein show "pronounced conformational flexibility" confined to the active site region of the protein and "enhanced" disorder at low pH, whereas the complex structures highlight significant differences in "ligand specificity" compared with the enzymatic subunit of a close homologue, Clostridium perfringens iota toxin. Specifically in CDTa, two of the suggested catalytically important residues (Glu-385 and Glu-387) seem to play no role or a less important role in ligand binding. These structural data provide the first detailed information on protein-donor substrate complex stabilization in CDTa, which may have implications in understanding CDT recognition.

Selected figure(s)

Figure 2.
Stereo view of ARTT loop in CDTa (native and NAD-bound form) and Ia (NAD-bound form).Green, CDTa-8.5; yellow, CDTa-9.0; cyan, CDTa-NAD; magenta, Ia-NAD. Residue numbering is according to CDTa (present structure). The corresponding residues in Ia are Tyr-375, Glu-378, and Glu-380.

Figure 4.
A, orientation of ARTT loop in CDTa (native and NAD bound form). B, orientation of loop 304, which shows differences between CDTa-4 and other structures. Green, CDTa-8.5; yellow, CDTa9.0; magenta, CDTa-4.0; cyan, CDTa-NAD.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2009, 284, 28713-28719) copyright 2009.

Figures were selected by an automated process.