The theoretical 3D structure of Bacillus thuringiensis Cry5Ba

Xia, Liqiu; Zhao, Xiao‐Fan; Ding, Xuezhi; Fa-Xiang, Wang; Sun, Yunjun

doi:10.1007/s00894-008-0318-8

Cited by 19 publications

(15 citation statements)

References 31 publications

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“…Crystal structure of Cry III A has been published first [62] and several others are now available. Xia et al [63] predicted the first theoretical model of the three dimensional (3D) structure of a Cry (Cry 5Ba) toxin by homology modeling on the structure of the Cry1Aa toxin, which is specific to Lepidopteran insects. The three-domain structure of CryIIIA consisted of the following: an α-helical barrel (domain I) which shows some resemblance to membrane-active or sporeforming domains of other toxins [64]; a triangular prism of "Greek key" beta sheets (domain II); and a β-sheet jelly-roll fold (domain III) [62].…”

Section: General Structure Of Cry Toxinmentioning

confidence: 99%

An Overview on the Crystal Toxins from <i>Bacillus thuringiensis</i>

Jisha¹,

Smitha²,

Benjamin³

2013

AiM

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Strains of Bacillus thuringiensis (Bt) are known to produce crystalline proteins (δ-endotoxins) concomitantly with sporulation during their stationary phase of growth, which are demonstrated as lethal to lepidopeterous, coleopeterous and dipterous insects in addition to mites, nematodes, protozoa and flukes. Upon ingestion, the δ-nascent endotoxin is an inactive protoxin complex of (Cry alone or Cry and Cyt toxins together) high molecular mass, which is cleaved upon ingestion into the active component proteins at the high alkaline environments in the digestive tract of these agricultural pests. Conventionally, Bt-crystals are being produced employing submerged or liquid fermentation techniques in commercial media, but recently many workers have used solid-state fermentation strategy for the enhanced production of Bt-toxin at low cost. Apart from δ-endotoxin, some isolates of Bt produce another class of insecticidal small molecules called β-exotoxin (thuringiensin), which may be harmful to humans. Moreover, resistance to Bt developed in various target pest is yet another concern for Bt-industry. Following a brief introduction, this review addresses various toxins produced by various strains of Bt, Bt production media and media formulations with emphasis to solid-state fermentation, general structure of Cry toxin, its mode of action, target pests, bioassay, resistance to Bt toxins and resistance management. Briefly, this review would provide the readers an overview on the general aspects of Bt toxin, its general structure and mechanism of action.

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Section: General Structure Of Cry Toxinmentioning

confidence: 99%

An Overview on the Crystal Toxins from <i>Bacillus thuringiensis</i>

Jisha¹,

Smitha²,

Benjamin³

2013

AiM

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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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“…Therefore, solution of the threedimensional structure of all Cry1 family members is important for further investigations. So far, crystal structures of the active toxins in solutions have been analyzed for Cry3A (Li et al, 1991), Cry1Aa (Grochulski et al, 1995), Cry1Ac (Derbyshire et al, 2001), Cry3B (Galitsky et al, 2001), Cry2A protoxin (Morse et al, 2001), Cry4Ba (Boonserm et al, 2005), Cry4Aa (Boonserm et al, 2006) by X-ray diffraction crystallography, and subsequently Cry11Bb (Gutierrez et al, 2001), Cry5Ba (Xia et al, 2008), and Cry5Aa (Min et al, 2009) have been predicted by the homology modeling method. These reports have shown that these toxins have three structural domains.…”

Section: Introductionmentioning

confidence: 99%

RESEARCH PAPER Homology modeling deduced tridimensional structure of Bacillus thuringiensis Cry1Ab18 toxin

Kashyap¹,

Singh²,

Amla³

2012

bta

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Cry1Ab18 is an δ-endotoxin produced by Bacillus thuringiensis strain. Till date the detailed mechanism of this toxin action is unclear. Therefore, solution of the three-dimensional structure of all Cry1 family members would be desirable for a comprehensive understanding of the initial mechanisms that underlie the toxicity of this type of toxin. Here, we predict a theoretical structural model of the newly reported Cry1Ab18 δ-endotoxin, using a homology modeling technique with the structure of Cry1Aa toxin molecule (resolution 2.25Å). Cry1Ab18 resembles Cry1Aa toxin by sharing a common three-domain structure. Domain I is composed of nine α helixes and one small β strand, domain II is composed of nine β strands and two α helixes and domain III consists of two α helixes and eleven β strands. This model supports the existing hypotheses of receptor insertion and will further provide the initiation point for the domain swapping experiments aimed towards improving protein toxicity, and will help in the deeper understanding of the mechanism of action of common toxins.

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The theoretical 3D structure of Bacillus thuringiensis Cry5Ba

Cited by 19 publications

References 31 publications

An Overview on the Crystal Toxins from <i>Bacillus thuringiensis</i>

An Overview on the Crystal Toxins from <i>Bacillus thuringiensis</i>

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

RESEARCH PAPER Homology modeling deduced tridimensional structure of Bacillus thuringiensis Cry1Ab18 toxin

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The theoretical 3D structure of Bacillus thuringiensis Cry5Ba

Cited by 19 publications

References 31 publications

An Overview on the Crystal Toxins from &lt;i&gt;Bacillus thuringiensis&lt;/i&gt;

An Overview on the Crystal Toxins from &lt;i&gt;Bacillus thuringiensis&lt;/i&gt;

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

RESEARCH PAPER Homology modeling deduced tridimensional structure of Bacillus thuringiensis Cry1Ab18 toxin

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An Overview on the Crystal Toxins from <i>Bacillus thuringiensis</i>

An Overview on the Crystal Toxins from <i>Bacillus thuringiensis</i>