TY - JOUR T1 - Cadherin-like receptor binding facilitates proteolytic cleavage of helix alpha-1 in domain I and oligomer pre-pore formation of Bacillus thuringiensis Cry1Ab toxin. AU - Gómez,Isabel, AU - Sánchez,Jorge, AU - Miranda,Raúl, AU - Bravo,Alejandra, AU - Soberón,Mario, PY - 2002/3/21/pubmed PY - 2002/4/17/medline PY - 2002/3/21/entrez SP - 242 EP - 6 JF - FEBS letters JO - FEBS Lett VL - 513 IS - 2-3 N2 - Cry toxins form lytic pores in the insect midgut cells. The role of receptor interaction in the process of protoxin activation was analyzed. Incubation of Cry1Ab protoxin with a single chain antibody that mimics the cadherin-like receptor and treatment with Manduca sexta midgut juice or trypsin, resulted in toxin preparations with high pore-forming activity in vitro. This activity correlates with the formation of a 250 kDa oligomer that lacks the helix alpha-1 of domain I. The oligomer, in contrast with the 60 kDa monomer, was capable of membrane insertion as judged by 8-anilino-1-naphthalenesulfonate binding. Cry1Ab protoxin was also activated to a 250 kDa oligomer by incubation with brush border membrane vesicles, presumably by the action of a membrane-associated protease. Finally, a model where receptor binding allows the efficient cleavage of alpha-1 and formation of a pre-pore oligomeric structure that is efficient in pore formation, is presented. SN - 0014-5793 UR - https://www.unboundmedicine.com/medline/citation/11904158/Cadherin_like_receptor_binding_facilitates_proteolytic_cleavage_of_helix_alpha_1_in_domain_I_and_oligomer_pre_pore_formation_of_Bacillus_thuringiensis_Cry1Ab_toxin_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0014579302023219 DB - PRIME DP - Unbound Medicine ER -