Mutant Vip3 Protein Engineering for High Plant Expression
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Solution Overview
Problem
Existing transgenic plants expressing Bt insecticidal proteins like Cry1Ab, Cry1Ac, Cry1F, Cry2Ab, and Vip3A proteins face challenges in achieving high expression and effective insect resistance, necessitating the development of mutant insecticidal proteins with improved efficacy.
Innovation Solution
A mutant insecticidal protein Vip3 is developed with specific amino acid mutations at positions 12 and 14, enhancing insecticidal activity and reducing plant cytotoxicity, encoded by a nucleotide sequence optimized for plant expression, and introduced via expression vectors and host cells to create insect-resistant transgenic plants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Vip3A protein is expressed in transgenic plants, then insect resistance is achieved, but plant cytotoxicity occurs reducing expression levels
Solution Approach 1:
The patent applies parameter changes by mutating specific amino acid residues in the Vip3A protein sequence. Two mutation strategies are employed: (1) mutating residue at position 12 from Alanine to Proline (A12P), and (2) mutating residue at position 14 from Proline to Aspartic acid (P14D). These parameter changes in the protein structure reduce plant cytotoxicity while preserving insecticidal activity, allowing higher expression levels in transgenic plants without harming the plant itself
Solution Approach 2:
The patent applies local quality by making targeted local modifications to the Vip3A protein sequence at specific positions (12 and 14). Instead of altering the entire protein structure, only two specific local regions are modified through site-directed mutagenesis. This localized approach maintains the overall functional integrity of the protein while eliminating the harmful cytotoxic effect on plants
2Reliability
If Bt insecticidal protein genes are transformed into plants, then insect-resistant plants are produced, but high expression and effective resistance are not simultaneously achieved
Solution Approach 1:
The patent resolves this contradiction through parameter changes in the protein sequence that reduce plant cytotoxicity. By mutating positions 12 and 14 of Vip3A, the modified protein becomes less harmful to plant cells, thereby enabling higher expression levels without compromising plant health. This results in both high productivity (expression level) and reliable insect resistance efficacy
Solution Approach 2:
The patent converts the harmful cytotoxicity of Vip3A into a benefit by strategically mutating residues that cause plant cell damage. The A12P and P14D mutations eliminate the harmful effect while preserving the insecticidal function, effectively transforming a detrimental property into an advantageous one that enables higher expression and better pest control
Data Source
AI summary
The present invention relates to the field of biotechnology. More specifically, the present invention relates to a mutant insecticidal protein Vip3 and its application. By performing point mutation on each original Vip3 family protein sequence in the present invention, a mutant insecticidal protein Vip3 with reduced plant cytotoxicity and high expression in plant cells is obtained, which has excellent insecticidal effects on various insect pests.