THE RECEPTOR FOR BACILLUS-THURINGIENSIS CRYLA(C) DELTA-ENDOTOXIN IN THE BRUSH-BORDER MEMBRANE OF THE LEPIDOPTERAN MANDUCA-SEXTA IS AMINOPEPTIDASE-N

A 120 kDa glycoprotein in the larval midgut membrane of the lepidopter an Manduca sexta, previously identified as a putative receptor for Bac illus thuringiensis CrylA(c) delta-endotoxin, has been purified by a c ombination of protoxin affinity chromatography and anion exchange chro matography. In immunoblotting experiments, the purified glycoprotein h as the characteristics predicted of the receptor: it binds CrylA(c) to xin in the presence of GlcNAc but not GalNAc; it binds the lectin SBA; but it does not bind CrylB toxin. N-terminal and internal amino acid sequences obtained from the protein show a high degree of similarity w ith the enzyme aminopeptidase N (EC 3.4.11.2). When assayed for aminop eptidase activity, purified receptor preparations were enriched 5.3-fo ld compared to M. sexta brush border membrane vesicles. We propose tha t the receptor for CrylA(c) toxin in the brush border membrane of the lepidopteran M. sexta is the metalloprotease aminopeptidase N.