A novel Vip3Aa16-Cry1Ac chimera toxin: Enhancement of toxicity against Ephestia kuehniella, structural study and molecular docking

Sellami, Slaheddine; Jemli, Sonia; Abdelmalek, Nouha; Cherif, Maroua; Abdelkefi-Mesrati, Lobna; Tounsi, Slim; Jamoussi, Kamel

doi:10.1016/j.ijbiomac.2018.05.161

Cited by 17 publications

(22 citation statements)

References 51 publications

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“…One of the main reasons for this is the lack of a high-resolution three-dimensional structure, which significantly impedes detailed molecular level functional and mechanistic studies and thus limits the development of their insecticidal potential. Accordingly, many groups have made great efforts to obtain or predict the atomic structure of Vip3A 21, 27, 28, 32, 33 . However, high-resolution crystal structure of Vip3 toxin family is still missing.…”

Section: Discussionmentioning

confidence: 99%

“…The scavenger receptor class C like protein (Sf-SR-C) and the fibroblast growth factor receptor (Fgfr) have been reported as potential receptors for Vip3A 13, 14 . However, although some in silico modeling efforts and low resolution cryo-EM structures have attempted to obtain structural insight for these toxins, the atomic structure of Vip3A is still not available, which makes it difficult to reveal the relationship between their structure and function 27, 28, 32, 33 .…”

Section: Introductionmentioning

confidence: 99%

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Structural insights into the insecticidal Vip3A toxin ofBacillus thuringiensis

Jiang

Zhang

Chen

et al. 2020

Preprint

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13 14 15 key words: Bacillus thuringiensis; Vip3A; biological control; 3D-structure; mode of 16 action; glycobiology 17 2 Abstract 39 The vegetative insecticidal proteins (Vips) secreted by Bacillus thuringiensis are 40 regarded as the new generation of insecticidal toxins because they have 41 different insecticidal properties compared with commonly applied insecticidal 42 crystal proteins (Cry toxins). Vip3A toxin, representing the vast majority of Vips, 43 has been used commercially in transgenic crops and bio-insecticides. However, 44 the lack of both structural information of Vip3A and a clear understanding of its 45 insecticidal mechanism at the molecular level, limits its further development and 46 broader application. Here we present the first crystal structure of the Vip3A toxin 47 in an activated form. Since all members of this insecticidal protein family are 48 highly conserved, the structure of Vip3A provides unique insight into the general 49 domain architecture and protein fold of the Vip3 family of insecticidal toxins. Our 50 structural analysis reveals a four-domain organization, featuring a potential 51 membrane insertion region, a receptor binding domain, and two glycan binding 52 domains of activated Vip3A. We further identify the specific glycan moieties 53 recognized by Vip3A through a glycan array screen. Taken together, these 54 findings provide insights into the mode of action of Vip3 family of insecticidal 55 toxins, and will boost the development of Vip3 into more efficient bio-56 insecticides. 57 58 59 60 61 62 63 64 3

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structural insights into the insecticidal Vip3A toxin ofBacillus thuringiensis

Jiang

Zhang

Chen

et al. 2020

Preprint

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“…We also detected bands smaller than 19 kDa by stopping the electrophoresis before they ran out of the gel. [11] for Vip3Aa (at residues 313, 532, and 667, respectively). The agreement between the domain limits proposed by us with some of those defined by in silico modelling supports the predictive value of the tryptic fragments approach to unravel structural domains of the Vip3A proteins.…”

Section: Discussionmentioning

confidence: 99%

“…For Vip3Af, five structural domains were proposed [4], with domain 1 spanning from the N-terminus to residue 188, domain 2 from residue 189 to 272, domain 3 from 273 to 542, domain 4 from 543 to 715, and domain 5 from 716 to the end. For Vip3Aa16, three domains were proposed, though domain 1 was further subdivided into three domains [11]: subdomain 1.1 spanned from the N-terminus to residue 313, subdomain 1.2.1 from 314 to 441, subdomain 1.2.2 from 442 to 532, domain 2 from 533 to 667, and domain 3 from 668 to the end. Given the high sequence similarity between the two proteins (92.7%), the discrepancy between them regarding the predicted regions spanned by the domains likely reflects inaccuracies of the modelling programs used.…”

Section: Introductionmentioning

confidence: 99%

Structural Domains of the <em>Bacillus thuringiensis</em> Vip3Af Protein Unraveled by Tryptic Digestion of Alanine Mutants

Quan

Ferré

2019

Preprint

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Vip3 proteins are increasingly used in insect control in transgenic crops. To shed light on the structure of these proteins, we used the approach of trypsin fragmentation of mutants altering the conformation of the Vip3Af protein. From an alanine scanning on Vip3Af, we selected mutants with an altered proteolytic pattern. Based on the protease digestion patterns, their effect on oligomer formation, and theoretical cleavage sites, we generated a map of the Vip3Af protein with five domains, which match some of the domains proposed independently by two in silico models. Domain I ranges from aa12-198, domain II from aa199-313, domain III from aa314-526, domain IV from aa527-668 and domain V from aa669-788. The effect of some of the mutations on the ability to form a tetrameric molecule revealed that domains I-III are required for tetramerization, while domain V is not. The involvement of domain IV in the tetramer formation is not clear. Some mutations distributed from near the end of domain I up to the end of domain II affect the stability of the first three domains of the protein and negatively impact oligomerization upon trypsin treatment. Because of the high sequence similarity among Vip3 proteins, we propose that our domain map can be extended to many other members of the Vip3 family of proteins.

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“…So far, the structure of Vip3A toxin has not been solved. Its structural information has been derived only by in-silico modeling [14,15], though the structure of the Vip3B was recently reported [16]. Studies on proteolytic activation of Vip3A proteins have shown that by a proteolytical process Vip3A protoxins are cleaved to become several major fragments, generally including fragments of 62-66 kDa, 45 kDa, 33 kDa and 19-22 kDa [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Oligomer Formation and Insecticidal Activity of Bacillus thuringiensis Vip3Aa Toxin

Shao

Zhang

et al. 2020

Toxins

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Bacillus thuringiensis (Bt) Vip3A proteins are important insecticidal proteins used for control of lepidopteran insects. However, the mode of action of Vip3A toxin is still unclear. In this study, the amino acid residue S164 in Vip3Aa was identified to be critical for the toxicity in Spodoptera litura. Results from substitution mutations of the S164 indicate that the insecticidal activity of Vip3Aa correlated with the formation of a >240 kDa complex of the toxin upon proteolytic activation. The >240 kDa complex was found to be composed of the 19 kDa and the 65 kDa fragments of Vip3Aa. Substitution of the S164 in Vip3Aa protein with Ala or Pro resulted in loss of the >240 kDa complex and loss of toxicity in Spodoptera litura. In contrast, substitution of S164 with Thr did not affect the >240 kDa complex formation, and the toxicity of the mutant was only reduced by 35%. Therefore, the results from this study indicated that formation of the >240 kDa complex correlates with the toxicity of Vip3Aa in insects and the residue S164 is important for the formation of the complex. Key Contribution:Our results correlated the formation of a >240 kDa protein complex with the insecticidal activity of Vip3Aa toxin. The residue S164 in Vip3Aa protein was identified to be important for the formation of the >240 kDa protein complex.

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A novel Vip3Aa16-Cry1Ac chimera toxin: Enhancement of toxicity against Ephestia kuehniella, structural study and molecular docking

Cited by 17 publications

References 51 publications

Structural insights into the insecticidal Vip3A toxin ofBacillus thuringiensis

Structural insights into the insecticidal Vip3A toxin ofBacillus thuringiensis

Structural Domains of the <em>Bacillus thuringiensis</em> Vip3Af Protein Unraveled by Tryptic Digestion of Alanine Mutants

Oligomer Formation and Insecticidal Activity of Bacillus thuringiensis Vip3Aa Toxin

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