The three-dimensional crystal structure of cholera toxin

Zhang, Rongguang; Westbrook, Mary L.; Nance, S.H.; Spangler, Brenda D.; Scott, David; Westbrook, Edwin M.

doi:10.2172/205782

Cited by 54 publications

(84 citation statements)

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“…The B protein subunit (CTB) contains five identical, non-covalently associated polypeptide chains (M r =11.6 kDa), arranged in a ring-like configuration (Zhang et al 1995). The CTB subunit is an edible vaccine candidate antigen (Daniell et al 2001).…”

Section: Resultsmentioning

confidence: 99%

Studies on the immunogenic potential of plant-expressed cholera toxin B subunit

et al. 2004

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Nicotiana tabacum var. Samsun was transformed via Agrobacterium-mediated transformation with a gene encoding the cholera toxin B subunit (CTB) of Vibrio cholerae, modified to contain a sequence coding for an endoplasmic reticulum retention signal (SEKDEL), under the control of the cauliflower mosaic virus 35S promoter. Total protein from the transgenic leaf tissue was isolated and an aliquot containing 5 microg recombinant CTB was injected intradermally into Balb/c (H2K(d)) mice. CTB-specific serum IgG was detected in animals that had been administered plant-expressed or native purified CTB. A T-cell proliferation study using splenocytes and cytokine estimations in supernatants generated by in vitro stimulation of macrophages isolated from the immuno-primed animals was carried out. Inhibition of proliferation of T lymphocytes was observed in splenic T lymphocytes isolated from animals injected with either native or plant-expressed CTB. Macrophages isolated from mice immunised with native or plant-expressed CTB showed enhanced secretion of interleukin-10 but secretion of lipopolysaccharide-induced interleukin-12 and tumor necrosis factor alpha was inhibited. These studies suggest that plant-expressed protein behaved like native CTB with regards to effects on T-cell proliferation and cytokine levels, indicating the suitability of plant expression systems for the production of bacterial antigens, which could be used as edible vaccine. The transgene was found to be inherited in the progeny and was expressed to yield a pentameric form of CTB as evident by its interaction with G(M1) ganglioside.

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Section: Resultsmentioning

confidence: 99%

Studies on the immunogenic potential of plant-expressed cholera toxin B subunit

et al. 2004

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“…Cholera toxin consists of one A subunit with enzymatic activity and five B subunits with binding activities to the host cells [23][24][25]. The cholera toxin binds to a lipid raft via G M1 -ganglioside for the internalization and activation of the toxin.…”

Section: Introductionmentioning

confidence: 99%

Expression of a Cholera Toxin B Subunit-Neutralizing Epitope of the Porcine Epidemic Diarrhea Virus Fusion Gene in Transgenic Lettuce (Lactuca sativa L.)

2010

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Transgenic plants have been used as a safe and economic expression system for the production of edible vaccines. A synthetic cholera toxin B subunit gene (CTB) was fused with a synthetic neutralizing epitope gene of the porcine epidemic diarrhea virus (sCTB-sCOE), and the sCTB-sCOE fusion gene was introduced into a plant expression vector under the control of the ubiquitin promoter. This plant expression vector was transformed into lettuce (Lactuca sativa L.) using the Agrobacterium-mediated transformation method. Stable integration and transcriptional expression of the sCTB-sCOE fusion gene was confirmed using genomic DNA PCR analysis and northern blot analysis, respectively. The results of western blot analysis with anti-cholera toxin and anti-COE antibody showed the synthesis and assembly of CTB-COE fusion protein into oligomeric structures with pentameric sizing. The biological activity of CTB-COE fusion protein to its receptor, G(M1)-ganglioside, in transgenic plants was confirmed via G(M1)-ELISA with anti-cholera toxin and anti-COE antibody. Based on G(M1)-ELISA, the expression level of CTB-COE fusion proteins reached 0.0065% of the total soluble protein in transgenic lettuce leaf tissues. Transgenic lettuce successfully expressing CTB-COE fusion protein will be tested to induce efficient immune responses against porcine epidemic diarrhea virus infection by administration with raw material.

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“…The conformation of this 'anchoring' segment is a-helical in CT (18) and ST (21), while in LT this segment is predominantly extended chain with a small terminal Photolabelling and surface pressure experiments indicate that the B subunits do not deeply penetrate into the membrane while bound to their ganglioside receptors (74)(75)(76)(77).…”

Section: The Central Pore (Doughnut Hole)mentioning

confidence: 99%

“…Members of the cholera enterotoxin family contain at least 20 epitopes that are recognizable by checkerboard immunoblotting. An epitope that includes Ala46 appears to choleragen is occupied by the helical terminus of the A2 chain in the holotoxin (18). with the purified peptide (VEVPGSQHIDSQKKA) induces partial protection from cholera.…”

Section: Cholera Toxin Is Anmentioning

confidence: 99%

“…The B subunits of CT, LT, ST, and PT share a conserved three-dimensional fold and oligomerize to form pentameric planar rings with a central "pore". The A subunit is anchored to the pentamer by a short polypeptide that extends down into the pore (18)(19)(20)(21)(22). In this re,port we describe the three-dimensional structure of cholera toxin's isolated B5 pentamer (choleragenoid).…”

mentioning

confidence: 99%

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