Crystal Structure of the C.perfringens Alpha-toxin with the Active Site Closed by a Flexible Loop Region

Eaton, Julian T.; Naylor, C.E.; Howells, Angela M.; Moss, David S.; Titball, Richard W.; Basak, A.K.

doi:10.1016/s0022-2836(02)00290-5

Cited by 39 publications

(33 citation statements)

References 37 publications

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“…Recent crystallographic studies have revealed that Cp-PLC exists in two conformations as follows: an open active form and a closed inactive form. In the open form three Zn 2ϩ ions are bound, and the active site is accessible (58). In the closed form there are only two Zn 2ϩ ions bound, and the active site is hindered by the loop encompassing residues 132-149 (58).…”

Section: Discussionmentioning

confidence: 99%

“…In the open form three Zn 2ϩ ions are bound, and the active site is accessible (58). In the closed form there are only two Zn 2ϩ ions bound, and the active site is hindered by the loop encompassing residues 132-149 (58). It is suggested that the binding of the Cp-PLC C-terminal domain to the target membrane induces a conformational change in the N-terminal domain, which uncovers the active site, allowing hydrolysis of the aggregated phospholipid substrates (58).…”

Section: Discussionmentioning

confidence: 99%

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A Cellular Deficiency of Gangliosides Causes Hypersensitivity to Clostridium perfringens Phospholipase C

Flores-Dı́az

Alape-Girón

Clark

et al. 2005

Journal of Biological Chemistry

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Clostridium perfringens phospholipase C (Cp-PLC), also called ␣-toxin, is the major virulence factor in the pathogenesis of gas gangrene. Previously, a cellular UDP-Glc deficiency was related with a hypersensitivity to the cytotoxic effect of Cp-PLC. Because UDP-Glc is required in the synthesis of proteoglycans, N-linked glycoproteins, and glycosphingolipids, the role of these glycoconjugates in the cellular sensitivity to Cp-PLC was studied. The cellular sensitivity to Cp-PLC was significantly enhanced by glycosphingolipid synthesis inhibitors, and a mutant cell line deficient in gangliosides was found to be hypersensitive to Cp-PLC. Gangliosides protected hypersensitive cells from the cytotoxic effect of Cp-PLC and prevented its membrane-disrupting effect on artificial membranes. Removal of sialic acids by C. perfringens sialidase increases the sensitivity of cultured cells to Cp-PLC and intramuscular co-injection of C. perfringens sialidase, and Cp-PLC in mice potentiates the myotoxic effect of the latter. This work demonstrated that a reduction in gangliosides renders cells more susceptible to the membrane damage caused by Cp-PLC and revealed a previously unrecognized synergism between Cp-PLC and C. perfringens sialidase, providing new insights toward understanding the pathogenesis of clostridial myonecrosis.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

A Cellular Deficiency of Gangliosides Causes Hypersensitivity to Clostridium perfringens Phospholipase C

Flores-Dı́az

Alape-Girón

Clark

et al. 2005

Journal of Biological Chemistry

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“…The findings from the present study and an earlier study (15) suggest that antibodies to conformational (rather than linear) epitopes of alpha-toxin are critical for protection against NE. Achieving conformational but nontoxic epitopes in a vaccine may prove challenging (1,7,33). Although many studies have emphasized the importance of the nontoxic C-terminal domain in offering protection against experimental gas gangrene (5,30,34), some have shown that the neutralizing epitopes are on the N terminus (18).…”

Section: Fig 3 Serum Igy Elisa Titers Of Broiler Chickens Immunizedmentioning

confidence: 99%

Immunization of Broiler Chickens against Clostridium perfringens -Induced Necrotic Enteritis

Kulkarni

Parreira

Sharif

et al. 2007

Clin Vaccine Immunol

124

118

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Necrotic enteritis (NE) in broiler chickens is caused by Clostridium perfringens. Currently, no vaccine against NE is available and immunity to NE is not well characterized. Our previous studies showed that immunity to NE followed oral infection by virulent rather than avirulent C. perfringens strains and identified immunogenic secreted proteins apparently uniquely produced by virulent C. perfringens isolates. These proteins were alphatoxin, glyceraldehyde-3-phosphate dehydrogenase, pyruvate:ferredoxin oxidoreductase (PFOR), fructose 1,6-biphosphate aldolase, and a hypothetical protein (HP). The current study investigated the role of each of these proteins in conferring protection to broiler chickens against oral infection challenges of different severities with virulent C. perfringens. The genes encoding these proteins were cloned and purified as histidine-tagged recombinant proteins from Escherichia coli and were used to immunize broiler chickens intramuscularly. Serum and intestinal antibody responses were assessed by enzyme-linked immunosorbent assay. All proteins significantly protected broiler chickens against a relatively mild challenge. In addition, immunization with alpha-toxin, HP, and PFOR also offered significant protection against a more severe challenge. When the birds were primed with alpha-toxoid and boosted with active toxin, birds immunized with alpha-toxin were provided with the greatest protection against a severe challenge. The serum and intestinal washings from protected birds had high antigen-specific antibody titers. Thus, we conclude that there are certain secreted proteins, in addition to alpha-toxin, that are involved in immunity to NE in broiler chickens.

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“…α-Toxin adopts two conformations: in the open or active structure, the active site contains three zinc ions and is accessible for substrate binding, whereas in the closed or inactive conformation, the two loops occlude the active site and one ion-binding site is lost. The binding of α-toxin to its membrane receptor through its C-terminal domain probably induces a conformational change of the N-terminal domain from the closed to the open configuration (Eaton et al, 2002).…”

Section: Plc (Phospholipase C) Activitymentioning

confidence: 99%

“…The active site would close after detachment from the membrane. Therefore, α-toxin can discriminate between phospholipids from intact and lysed cells, resulting in an increase in cell lysis (Eaton et al, 2002).…”

Section: Figure 2 Cellular Disturbances Induced By Bacterial Toxins Amentioning

confidence: 99%

Bacterial protein toxins and lipids: role in toxin targeting and activity

Geny

Popoff

2006

Biology of the Cell

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All bacterial toxins, which globally are hydrophilic proteins, interact first with their target cells by recognizing a surface receptor, which is either a lipid or a lipid derivative, or another compound but in a lipid environment. Intracellular active toxins follow various trafficking pathways, the sorting of which is greatly dependent on the nature of the receptor, notably lipidic receptor or receptor embedded into a distinct environment such as lipid microdomains. Numerous other toxins act locally on cell membrane. Indeed, phospholipase activity is a common mechanism shared by several membrane‐damaging toxins. In addition, many toxins active intracellularly or on cell membrane modulate host cell phospholipid pathways. Unusually, a few bacterial toxins require a lipid post‐translational modification to be active. Thereby, lipids are obligate partners of bacterial toxins.

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Crystal Structure of the C.perfringens Alpha-toxin with the Active Site Closed by a Flexible Loop Region

Cited by 39 publications

References 37 publications

A Cellular Deficiency of Gangliosides Causes Hypersensitivity to Clostridium perfringens Phospholipase C

A Cellular Deficiency of Gangliosides Causes Hypersensitivity to Clostridium perfringens Phospholipase C

Immunization of Broiler Chickens against Clostridium perfringens -Induced Necrotic Enteritis

Bacterial protein toxins and lipids: role in toxin targeting and activity

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