A theoretical model of the tridimensional structure of Bacillus thuringiensis subsp. medellin Cry 11Bb toxin deduced by homology modelling

Gutiérrez, Pablo; Álzate, Óscar; Ordúz, Sergio

doi:10.1590/s0074-02762001000300013

Cited by 24 publications

(14 citation statements)

References 36 publications

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“…medellin as a 94-kDa protein composed of 782 amino acid residues (56), and its three-dimensional structure with nine ␣ helixes in the domain I has been proposed earlier (57). This protein is toxic for mosquito larvae (44, 56) after activation by mosquito larvae midgut proteases (58) and further membrane binding and permeabilization of the midgut epithelial cells (59).…”

Section: Discussionmentioning

confidence: 99%

Mitochondria Permeabilization by a Novel Polycation Peptide BTM-P1

Lemeshko

Arias

Ordúz

2005

Journal of Biological Chemistry

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Bacillus thuringiensis subsp. medellin is known to produce the Cry11Bb protein of 94 kDa, which is toxic for mosquito larvae due to permeabilization of the plasma membrane of midgut epithelial cells. Earlier we found that a 2.8-kDa novel peptide BTM-P1, which was artificially synthesized taking into account the primary structure of Cry11Bb endotoxin, is active against several species of bacteria. In this work we show that BTM-P1 induces cyclosporin A-insensitive swelling of rat liver mitochondria in various salt solutions but not in the sucrose medium. Inorganic phosphate and Ca 2؉ significantly increased this effect of the peptide. The uncoupling action of BTM-P1 on oxidative phosphorylation was stronger in the potassiumcontaining media and correlated with a decrease of the inner membrane potential of mitochondria. In isotonic KNO 3 , KCl, or NH 4 NO 3 media, a complete drop of the inner membrane potential was observed at 1-2 g/ml of the peptide. The peptide-induced swelling was increased by energization of mitochondria in the potassium-containing media, but it was inhibited in the NaNO 3 , NH 4 NO 3 , and Tris-NO 3 media. All mitochondrial effects of the peptide were completely prevented by adding a single N-terminal tryptophan residue to the peptide sequence. We suggest a mechanism of membrane permeabilization that includes a transmembrane-and surface potential-dependent insertion of the polycation peptide into the lipid bilayer and its oligomerization leading to formation of ion channels and also to the mitochondrial permeability transition pore opening in a cyclosporin A-insensitive manner.

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Section: Discussionmentioning

confidence: 99%

Mitochondria Permeabilization by a Novel Polycation Peptide BTM-P1

Lemeshko

Arias

Ordúz

2005

Journal of Biological Chemistry

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“…29) Cry11Bb is also a dipteranspeciˆc insecticidal protein of 94 kDa produced by B. thuringiensis subsp. medellin, 30) and shares the 51z identity of amino acid sequence with Cry11Aa.…”

Section: Discussionmentioning

confidence: 99%

Active Form of Dipteran-Specific Insecticidal Protein Cry11A Produced byBacillus thuringiensissubsp.israelensis

Yamagiwa

Ogawa

Yasuda

et al. 2002

Bioscience, Biotechnology, and Biochemistry

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“…So far, Cry1 toxins have extensively been used in studies of insect control either as transgenic spores or as spray formulations. Where three-dimensional crystal structure of Cry1 family of protein is concerned, few of the toxins in solutions have been analysed by X-ray diffraction crystallography [3–9], and a few of them have been predicted using the homology modelling method [10–12]. All these toxins have a different toxicity spectrum; in spite of this, these proteins show a similar tertiary organization.…”

Section: Introductionmentioning

confidence: 99%

In SilicoModeling and Functional Interpretations of Cry1Ab15 Toxin fromBacillus thuringiensisBtB-Hm-16

Kashyap

2013

BioMed Research International

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The theoretical homology based structural model of Cry1Ab15 δ-endotoxin produced by Bacillus thuringiensis BtB-Hm-16 was predicted using the Cry1Aa template (resolution 2.25 Å). The Cry1Ab15 resembles the template structure by sharing a common three-domain extending conformation structure responsible for pore-forming and specificity determination. The novel structural differences found are the presence of β0 and α3, and the absence of α7b, β1a, α10a, α10b, β12, and α11a while α9 is located spatially downstream. Validation by SUPERPOSE and with the use of PROCHECK program showed folding of 98% of modeled residues in a favourable and stable orientation with a total energy Z-score of −6.56; the constructed model has an RMSD of only 1.15 Å. These increments of 3D structure information will be helpful in the design of domain swapping experiments aimed at improving toxicity and will help in elucidating the common mechanism of toxin action.

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A theoretical model of the tridimensional structure of Bacillus thuringiensis subsp. medellin Cry 11Bb toxin deduced by homology modelling

Abstract: Cry11Bb is an insecticidal crystal protein produced by

Cited by 24 publications

References 36 publications

Mitochondria Permeabilization by a Novel Polycation Peptide BTM-P1

Mitochondria Permeabilization by a Novel Polycation Peptide BTM-P1

Active Form of Dipteran-Specific Insecticidal Protein Cry11A Produced byBacillus thuringiensissubsp.israelensis

In SilicoModeling and Functional Interpretations of Cry1Ab15 Toxin fromBacillus thuringiensisBtB-Hm-16

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