Cry1A.105 Chimeric Insecticidal Protein Design
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Solution Overview
Problem
Current methods for creating chimeric insecticidal proteins effective against lepidopteran pests are challenging due to the complex nature of protein structure and folding, leading to inefficient insecticidal activity and potential resistance issues in transgenic crops.
Innovation Solution
Development of isolated nucleotide sequences encoding the Cry1A.105 protein, which can be expressed in plants to produce a novel insecticidal protein with enhanced bioactivity and stability, delaying resistance onset when combined with other insecticidal proteins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chimeric insecticidal proteins are created through reassortment of domain structures from multiple native proteins, then insecticidal activity may be enhanced, but the complexity of protein structure and folding makes successful creation highly improbable and inefficient
Solution Approach 1:
The Cry1A.105 protein is divided into three functional domains (Domain I, Domain II, and Domain III) with distinct roles: Domain I for channel formation, and Domains II and III for receptor binding and species specificity. This segmentation allows systematic construction of chimeric proteins by recombining specific domains from different parental proteins rather than attempting random reassortment of entire structures.
Solution Approach 2:
Different domains of the chimeric protein are assigned specific functional qualities: Domain I provides the pore-forming capability, while Domains II and III provide species-specific binding properties. This local quality assignment allows optimization of each domain's function independently, improving overall reliability of insecticidal activity while managing structural complexity.
2Productivity
If higher expression levels of insecticidal proteins are achieved in transgenic crops, then pest control effectiveness is improved, but the complex nature of protein folding and crystal formation may lead to faulty crystal structure and reduced activity
Solution Approach 1:
The chimeric Cry1A.105 protein is designed with pre-optimized domain combinations before expression in plants. The precursor protein structure is engineered to facilitate proper folding and crystal formation, ensuring that high expression levels produce functional toxin segments rather than misfolded aggregates.
Solution Approach 2:
The chimeric protein combines elements from different parental Cry proteins to create a composite structure with improved properties. The fusion of Domain I from one protein with Domains II and III from another creates a hybrid molecule that maintains stability and folding efficiency at high expression levels while enhancing insecticidal activity.
3Reliability
If conventional Bt crystal proteins are used for pest control, then lepidopteran insect larvae are controlled, but insects may develop resistance over time
Solution Approach 1:
The chimeric Cry1A.105 protein modifies key parameters of the toxin structure, particularly in Domains II and III which determine species specificity and receptor binding. These parameter changes create a novel toxin that maintains effectiveness against resistant insect populations by targeting different or additional receptors compared to conventional Bt proteins.
Data Source
AI summary
The present invention provides nucleotide sequences encoding an insecticidal protein exhibiting lepidopteran inhibitory activity, as well as a novel insecticidal protein referred to herein as a Cry1A.105 insecticide, transgenic plants expressing the insecticide, and methods for detecting the presence of the nucleotide sequences or the insecticide in a biological sample.