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#Bacillus thuringiensis

16 public questions tagged with this topic.

Transgenic Plant -1

Cry proteins become toxic after:

Bt protoxins are inert in plant tissues because solubilization and cleavage conditions absent in neutral pH plant cells. Upon ingestion by susceptible larvae, midgut lumen alkalinity dissociates crystal lattice, releasing soluble protoxin. Midgut serine proteases like trypsin and chymotrypsin cleave N-terminus 28 and C-terminus half, exposing hydrophobic helix alpha-1 for membrane insertion. Resulting 60 to 65 kDa toxin undergoes conformational change induced by cadherin receptor binding, leading to oligomerization into pre-pore tetramer that inserts into apical microvilli causing osmotic imba

Ref: Bravo Biochim Biophys Acta 2007 activation; NCBI NBK24601; Pardo-Lopez Peptides 2013 cleavage; PubMed 16885436.

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Transgenic Plant -1

Bacillus thuringiensis produces insecticidal protein called:

During late sporulation, Bacillus thuringiensis forms intracellular parasporal crystals alongside spores. Protein components are protoxins referred to as delta-endotoxins because they act within insect midgut after ingestion and are endotoxin-like in crystal formation. Sequence classification divides them into Cry families sharing three-domain structure: domain I seven antiparallel alpha-helices responsible for pore formation, domain II beta prism determining receptor specificity, domain III beta sandwich stabilizing structure. Crystal solubilization requires alkaline pH above 9.5 common in le

Ref: Schnepf Microbiol Mol Biol Rev 1998 delta-endotoxin; NCBI NBK24601 Cry proteins; Crickmore Microbiol Rev 1998 nomenclature; https://www.ncbi.nlm.nih.gov/books/NBK24601/

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