title: [Relationship between structure and function of loops from Bacillus thuringiensis insecticidal crystal protein Cry1Ba].
abstract: To indicate the relationship between structure and function of loops from Bacillus thuringiensis insecticidal crystal protein Cry1Ba, and the influence of amino acids mutation on toxicity against diamond back moth Plutella xylostella, five mutations at the loops of Cry1Ba were constructed by overlapping primer PCR, and expressed in E. coli BL21 (DE3). Bioassay results showed that the toxicity of mutation M1 (loop1: 340WSNTR344-deletion), compared with that of Cry1Ba (LC50 0.96 microg/mL), decreased significantly with LC50 35.51 microg/mL. And the toxicity of mutation M2 (402Y-G), M3 (400GIYLEP405-PSAV), M4 (400GIYLEPIH407-ILGS) was also reduced to some extent respectively. Only M5 (mutation at loop3: 472LQSRV476 - AGAVYTL) showed slightly increased activity against P. xylostella, but not significantly (LC50 0.81 microg/mL). Referring to the structures of Cry1Ba which was predicted using Swiss-Model software, and bioassay data, we can conclude that loop1 and loop2 play a important role on determining the activity of Cry1Ba against P. xylostella.
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
authors.forename: Guangjun
authors.initials: G
authors.lastname: Wang
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Donghui
authors.initials: D
authors.lastname: Sun
authors.forename: Fuping
authors.initials: F
authors.lastname: Song
authors.forename: Dafang
authors.initials: D
authors.lastname: Huang
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics* / Q000378:metabolism; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D004731:Endotoxins / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D006460:Hemolysin Proteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D009036:Moths / Q000382:microbiology; D009154:Mutation; D017433:Protein Structure, Secondary; D013329:Structure-Activity Relationship
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis