Mandal Chandi C, Gayen Srimonta, Basu Asitava, Ghosh Kalyan S, Dasgupta Swagata, Maiti Mrinal K, Sen Soumitra K
IIT - BREF Biotek, Indian Institute of Technology, Kharagpur-721 302, India.
Protein Eng Des Sel. 2007 Dec;20(12):599-606. doi: 10.1093/protein/gzm058. Epub 2007 Nov 29.
Issues relating to sustenance of the usefulness of genetically modified first generation Bt crop plants in the farmer's field are of great concern for crop scientists. Additional biotechnological strategies need to be in place to safeguard the possibility for yield loss of Bt crop by other lepidopteran insects that are insensitive to the Cry1A toxin, and also against the possibility for emergence of resistant insects. In this respect, Cry2A toxin has figured as a prospective candidate to be the second toxin to offer the required protection along with Cry1A. In the present study, the entomocidal potency of Cry2A toxin was enhanced through knowledge-based protein engineering of the toxin molecule. Deletion of 42 amino acid residues from the N-terminal end of the peptide followed by the replacement of Lys residues by nonpolar amino acids in the putative transmembrane region including the introduction of Pro resulted in a 4.1-6.6-fold increase in the toxicity of the peptide against three major lepidopteran insect pests of crop plants.
转基因第一代Bt作物在农田中的有效性维持相关问题，是作物科学家极为关注的。需要制定额外的生物技术策略，以防范对Cry1A毒素不敏感的其他鳞翅目昆虫导致Bt作物减产的可能性，以及抗性昆虫出现的可能性。在这方面，Cry2A毒素已被视为有望与Cry1A一起提供所需保护的第二种毒素。在本研究中，通过基于知识的毒素分子蛋白质工程提高了Cry2A毒素的杀虫效力。从肽的N末端删除42个氨基酸残基，随后在包括引入Pro的推定跨膜区域用非极性氨基酸取代Lys残基，导致该肽对作物的三种主要鳞翅目害虫的毒性增加了4.1至6.6倍。
