Cry - Pesticidal crystal proteins
Members of this family are proteins/peptides, synthesized by one cell and secreted for insertion into the membrane of another cell where they form transmembrane pores. Pore-forming toxins (PFTs) are the most common bacterial cytotoxic proteins and are required for virulence in a large number of important pathogens.
Over 100 subgroups belong to the "Pore-forming Toxins" family, including amongst others:
- The α-Hemolysin Channel-forming Toxin (αHL) Family
- The Aerolysin Channel-forming Toxin (Aerolysin) Family
- The Botulinum and Tetanus Toxin (BTT) Family
- The Pertussis Toxin (PTX) Family
- The Crystal Protein (Cry) Family
Cry Proteins Background Information
Pesticidal crystal "Cry" proteins, also called Insecticidal delta-endotoxin, are a product of Bacillus thuringiensis. During sporulation, the bacillus produces these pore-forming toxins which have insecticidal action. This has led to their use as insecticides, and more recently to genetically modified crops using Bt genes.
When insects ingest toxin crystals, their alkaline digestive tracts denature the insoluble crystals, making them soluble and thus amenable to being cut with proteases found in the insect gut, which liberate the toxin from the crystal. The Cry toxin is then inserted into the insect gut cell membrane, paralyzing the digestive tract and forming a pore.
cry1Aa, cry2Aa, cry3Aa and several more
Proteins (3 examples):
UniProt P0A379, UniProt P0A377, UniProt P0A367
Promotes colloidosmotic lysis by binding to the midgut epithelial cells of many lepidopteran larvae.
Bilayer Recordings on the Orbit Instrument family
Reviews and Links
- Palma et al. (2014) Bacillus thuringiensis Toxins: An Overview of Their Biocidal Activity. Toxins 2014, 6, 3296-3325; doi:10.3390/toxins6123296
Transporter classification database:
- 1.C.2 The Channel-forming δ-Endotoxin Insecticidal Crystal Protein (ICP) Family
- 1.C.78 The Crystal Protein (Cry) Family
- Pesticidal crystal protein Cry3Aa (cry3Aa, Bacillus thuringiensis subsp. tenebrionis)
- Pesticidal crystal protein Cry2Aa (cry2Aa, Bacillus thuringiensis subsp. kurstaki)
- Pesticidal crystal protein Cry1Aa (cry1Aa, Bacillus thuringiensis subsp. aizawai)