Effect of C-terminus site-directed mutations on the toxicity and sensitivity of<i>Bacillus thuringiensis</i>Vip3Aa11 protein against three lepidopteran pests

Chi, Baoyan; Luo, Guangwen; Zhang, Jinbo; Sha, Junxue; Liu, Rongmei; Li, Haitao; Gao, Jiguo

doi:10.1080/09583157.2017.1399309

Cited by 8 publications

(8 citation statements)

References 28 publications

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“…Similarly, the docking and binding site prediction analysis identified the amino acids Y616, H618, Y619, W552, K557, E627, and Q652 in the Ct region as crucial sites for Vip3Aa toxin binding and insecticidal activity. The insecticidal activity of only one mutant, Y619A, was increased against H. armigera and S. exigua [38]. In another case, the Vip3Aa protein substitutions at site S164 with alanine or proline resulted in a loss of oligomer formation, and an ablation of the insecticidal potential against S. litura.…”

Section: Effect Of Amino Acid Modifications On Toxicity Of Mutant Vip3amentioning

confidence: 96%

“…Meanwhile, Vip3A11 mutants are generated after replacing nine residues at the C-terminus with Vip3A39 residues by site-targeted mutagenesis. Here, the cysteine residue CYS784 of the C-terminal region is found to be a crucial trypsin cleave site for bioactivity and toxicity [38]. However, the Vip3 C-terminal region alone does not possess an insecticidal activity, as the expression and purification of the C-terminal region of Vip3Ab1 and Vip3Bc1 cause no harm to the insects.…”

Section: Structure and Function Of Vip3 Proteinsmentioning

confidence: 99%

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Current Insights on Vegetative Insecticidal Proteins (Vip) as Next Generation Pest Killers

Syed

Askari

Meng

et al. 2020

Toxins

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Bacillus thuringiensis (Bt) is a Gram negative soil bacterium. This bacterium secretes various proteins during different growth phases with an insecticidal potential against many economically important crop pests. One of the important families of Bt proteins is vegetative insecticidal proteins (Vip), which are secreted into the growth medium during vegetative growth. There are three subfamilies of Vip proteins. Vip1 and Vip2 heterodimer toxins have an insecticidal activity against many Coleopteran and Hemipteran pests. Vip3, the most extensively studied family of Vip toxins, is effective against Lepidopteron. Vip proteins do not share homology in sequence and binding sites with Cry proteins, but share similarities at some points in their mechanism of action. Vip3 proteins are expressed as pyramids alongside Cry proteins in crops like maize and cotton, so as to control resistant pests and delay the evolution of resistance. Biotechnological- and in silico-based analyses are promising for the generation of mutant Vip proteins with an enhanced insecticidal activity and broader spectrum of target insects.

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Section: Effect Of Amino Acid Modifications On Toxicity Of Mutant Vip3amentioning

confidence: 96%

Section: Structure and Function Of Vip3 Proteinsmentioning

confidence: 99%

Current Insights on Vegetative Insecticidal Proteins (Vip) as Next Generation Pest Killers

Syed

Askari

Meng

et al. 2020

Toxins

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“…The amino acids S543, I544, W552, N624, E627, and S686 in Vip3Aa were selected for mutagenesis because modification of these sites previously changed toxicity to S. exigua, A. ipsilon, and H. armigera. 21,22 Multiple mutants were constructed, including Vip3Aa-S543N/I544L, Vip3Aa-N624A/E627A, Vip3Aa-S543N/ I544L/E627A, and Vip3Aa-S543N/I544L/S686R. Heterologously expressed Vip3Aa mutants in E. coli were approximately 85 kDa (Fig.…”

Section: Mutagenesis Of Vip3aa Increased Insecticidal Activity Agains...mentioning

confidence: 99%

“…20 Meanwhile, a series of single mutants at the C-terminus of Vip3Aa constructed in our laboratory showed significantly different activity against A. ipsilon, S. exigua, or H. armigera. 21,22 In this study, double and triple mutants in domains IV and V of Vip3Aa11 were constructed. Two triple mutants (Vip3Aa-S543N/ I544L/E627A and Vip3Aa-S543N/I544L/S686R) exhibited enhanced insecticidal activity against S. frugiperda and H. armigera, but not S. litura, S. exigua, and Mythimna separata.…”

Section: Introductionmentioning

confidence: 99%

Vip3Aa domain IV and V mutants confer higher insecticidal activity against Spodoptera frugiperda and Helicoverpa armigera

Yang

Wang

et al. 2022

Pest Management Science

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BACKGROUND The fall armyworm Spodoptera frugiperda and cotton bollworm Helicoverpa armigera are major insect pests of corn and cotton worldwide. Genetically engineered crops producing Vip3Aa, a potent endotoxin, from the bacterium Bacillus thuringiensis (Bt) are effective in controlling these two harmful pests. However, Vip3Aa efficacy is relatively weak compared to that of other Bt proteins such as Cry1A and Cry1F. This study sought to modify Vip3Aa for increased insecticidal activity and determine the cause of elevated activity. RESULTS The two triple Vip3Aa mutants in domains IV and V (Vip3Aa‐S543N/I544L/E627A and Vip3Aa‐S543N/I544L/S686R) exhibited 7.3‐fold and 2.8‐fold increased toxicity against S. frugiperda, respectively, compared with the wild type while the toxicity of Vip3Aa‐S543N/I544L/S686R was 3.2 times that of wild‐type protein in H. armigera. The mutants had enhanced stability in midgut juice and 2.6–5.1 times higher binding affinity against S. frugiperda and H. armigera compared with wild type protein. CONCLUSIONS The enhanced toxicity of Vip3Aa mutants was due to increased stability and binding affinity during infection. The amino acids S543 and I544 combined with E627 or S686 in domains IV and V of Vip3Aa are important for maintaining structural stability and receptor binding. The results match insecticidal activity (LC50) with binding activity (Kd), which provides novel clues for the rational design of Bt insecticidal proteins. © 2022 Society of Chemical Industry.

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“…Ward et al (1988) mutated acidic and basic amino acids into alanine to explore its role in polar phospholipid group interaction. Chi et al (2018) and Luo et al (2018) applied site-directed mutagenesis in the study of key sites of the insecticidal activity of Vip3Aa11 protein. Yang et al (2014) applied site-directed mutagenesis in the study of improving the activity and stability of the enzyme.…”

Section: Introductionmentioning

confidence: 99%

In silico Structure–Based Investigation of Key Residues of Insecticidal Activity of Sip1Aa Protein

et al. 2020

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Colaphellus bowringi Baly mainly damages cruciferous vegetables, leading to huge economic losses. The secretory insecticidal protein (Sip) of Bacillus thuringiensis (Bt) has high insecticidal activity against C. bowringi Baly. The tertiary structure of Sip1Aa protein was analyzed by homologous modeling and other bioinformatics methods to predict the conserved domain of Sip1Aa protein. Acidic and basic amino acids in the conserved domain were selected, and alanine was used to replace these amino acids by site-directed mutation. The difference between the insecticidal activities of mutant protein and Sip1Aa protein was analyzed. The insecticidal activities of H99A, K109A, K128A, and E130A against C. bowringi Baly were significantly increased, among which that of K128A was the most obviously changed, and the LC 50 value was decreased by about 10 times compared with that of Sip1Aa protein. The LC 50 value of mutant E130A was 0.286 µg/mL, which was about six times less than that of Sip1Aa. K128 and E130 were both in the β9-β10 loop. The toxicity of D290A, H242A, and H303A to C. bowringi Baly was significantly reduced, and their LC 50 value increased by about six, eight, and three times compared with that of Sip1Aa protein, respectively. This study showed that acidic and basic amino acid residues played a certain role in the toxicity of Sip1Aa protein, and the loss of side chains in key residues had a significant impact on the insecticidal activity of the protein. This study provides the theoretical basis for revealing the relationship between the structure and function of Sip1Aa protein and also provides a new method for the subsequent study of sip gene.

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Effect of C-terminus site-directed mutations on the toxicity and sensitivity ofBacillus thuringiensisVip3Aa11 protein against three lepidopteran pests

Cited by 8 publications

References 28 publications

Current Insights on Vegetative Insecticidal Proteins (Vip) as Next Generation Pest Killers

Current Insights on Vegetative Insecticidal Proteins (Vip) as Next Generation Pest Killers

Vip3Aa domain IV and V mutants confer higher insecticidal activity against Spodoptera frugiperda and Helicoverpa armigera

In silico Structure–Based Investigation of Key Residues of Insecticidal Activity of Sip1Aa Protein

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