Structure and Action of the Binary C2 Toxin from Clostridium botulinum

Schleberger, Christian; Hochmann, Henrike; Barth, Holger; Aktories, Klaus; Schulz, Georg E.

doi:10.1016/j.jmb.2006.09.002

Cited by 120 publications

(138 citation statements)

References 45 publications

(56 reference statements)

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“…1B) is reflected at the structural level; when comparing the three-dimensional structure of CDTa (present study, Fig. 1A) with those of previously reported crystallographic results on Ia (21), C. botulinum C2 toxin (28), and ADPRT component, VIP2 (vegetative insecticidal protein) (29) ( Table 2), all of them are composed of two mixed ␣/␤ globular domains. For comparison purposes we restrict our discussion on CDTa with Ia.…”

Section: Resultssupporting

confidence: 82%

Structural Basis for Substrate Recognition in the Enzymatic Component of ADP-ribosyltransferase Toxin CDTa from Clostridium difficile

Sundriyal

Roberts²,

Shone³

et al. 2009

Journal of Biological Chemistry

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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.Clostridium difficile infection is a major problem as a healthcare-associated infection. The bacterium causes nosocomial, antibiotic-associated diarrhea and pseudomembranous colitis in patients treated with broad spectrum antibiotics (1-3). Elderly patients are most at risk from these potentially life-threatening diseases, and incidents of hospital infection have increased dramatically over the last 10 years.Strains of C. difficile produce a variety of virulence factors, notable among which are several protein toxins: Toxin A, Toxin B (4 -6), and, in some strains, the binary toxin CDT, 3 which is similar to Clostridium perfringens iota toxin and Clostridium botulinum C2 toxin (7-9). Toxins A and B are large protein cytotoxins that play a key role in the pathology of infection and most probably are involved in the gut colonization process. Outbreaks of C. difficile infection have been reported with Toxin A-negative/Toxin B-positive strains, and a recent report (10) suggests that Toxin B plays a major role in the disease pathology. Little is presently known about the contribution of the binary toxin to C. difficile infection.CDT binary toxin belongs to the family of actin-specific ADP-ribosylating toxin (ADPRT) (for a recent review see Ref.11), composed of two independently produced components: a transport component of 99 kDa (CDTb) that facilitates translocation of the enzymatic component of 49 kDa (CDTa) into the target cell that is capable of transferring ADP-ribose group of NAD/NADPH to monomeric actin molecules in target cells (9,12,13). This irreversible modification of G-actin at 14) blocks its polymerization and thus...

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Section: Resultssupporting

confidence: 82%

Structural Basis for Substrate Recognition in the Enzymatic Component of ADP-ribosyltransferase Toxin CDTa from Clostridium difficile

Sundriyal

Roberts²,

Shone³

et al. 2009

Journal of Biological Chemistry

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“…The 3D structures of several protein ADP-ribosyltransferases have been reported including chicken poly(ADP-ribose) polymerase (PARP)-1 (14), rat ART2.2 (15), mosquitocidal toxin from Bacillus sphaericus (16), diphtheria toxin (17), cholera toxin (18), domain III of Pseudomonas aeruginosa exotoxin A (19), iota-toxin from Clostridium perfringens (20), pertussis toxin (21), C2-toxin (22), and C3-toxin (23) from Clostridium botulinum.…”

mentioning

confidence: 99%

Rifamycin antibiotic resistance by ADP-ribosylation: Structure and diversity of Arr

Baysarowich

Koteva

Hughes

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

164

196

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The rifamycin antibiotic rifampin is important for the treatment of tuberculosis and infections caused by multidrug-resistant Staphylococcus aureus. Recent iterations of the rifampin core structure have resulted in new drugs and drug candidates for the treatment of a much broader range of infectious diseases. This expanded use of rifamycin antibiotics has the potential to select for increased resistance. One poorly characterized mechanism of resistance is through Arr enzymes that catalyze ADP-ribosylation of rifamycins. We find that genes encoding predicted Arr enzymes are widely distributed in the genomes of pathogenic and nonpathogenic bacteria. Biochemical analysis of three representative Arr enzymes from environmental and pathogenic bacterial sources shows that these have equally efficient drug resistance capacity in vitro and in vivo. The 3D structure of one of these orthologues from Mycobacterium smegmatis was determined and reveals structural homology with ADP-ribosyltransferases important in eukaryotic biology, including poly(ADP-ribose) polymerases (PARPs) and bacterial toxins, despite no significant amino acid sequence homology with these proteins. This work highlights the extent of the rifamycin resistome in microbial genera with the potential to negatively impact the expanded use of this class of antibiotic.crystallography ͉ resistome ͉ rifampin ͉ ribosyltransferase

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“…This binary C2 toxin is composed of the enzyme component C2I, which ADP-ribosylates monomeric G-actin, and the binding and translocation component C2II, which is responsible for the interaction with a eukaryotic cell membrane receptor and the ensuing endocytosis (20). Previous studies showed that the enzymatic component C2I is an ϳ49-kDa protein, whereas the inactive binding component C2II has a mass of ϳ80 kDa (1,15).…”

mentioning

confidence: 99%

Functional Characterization of an Extended Binding Component of the Actin-ADP-Ribosylating C2 Toxin Detected in Clostridium botulinum Strain (C) 2300

et al. 2010

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Clostridium botulinum C2 toxin consists of the binding component C2II and the enzyme component C2I, which ADP-ribosylates G-actin of eukaryotic cells. Trypsin-activated C2II (C2IIa) forms heptamers that mediate cell binding and translocation of C2I from acidic endosomes into the cytosol of target cells. By genome sequencing of C. botulinum strain (C) 2300, we found that C2II from this strain carries a C-terminal extension of 129 amino acids, unlike its homologous counterparts from strains (C) 203U28, (C) 468, and (D) 1873. This extension shows a high similarity to the C-terminal receptor-binding domain of C2II and is presumably the result of a duplication of this domain. The C2II extension facilitates the binding to cell surface receptors, which leads to an increased intoxication efficiency compared to that of C2II proteins from other C. botulinum strains.

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Structure and Action of the Binary C2 Toxin from Clostridium botulinum

Cited by 120 publications

References 45 publications

Structural Basis for Substrate Recognition in the Enzymatic Component of ADP-ribosyltransferase Toxin CDTa from Clostridium difficile

Structural Basis for Substrate Recognition in the Enzymatic Component of ADP-ribosyltransferase Toxin CDTa from Clostridium difficile

Rifamycin antibiotic resistance by ADP-ribosylation: Structure and diversity of Arr

Functional Characterization of an Extended Binding Component of the Actin-ADP-Ribosylating C2 Toxin Detected in Clostridium botulinum Strain (C) 2300

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