S.no

Domain

Amino acid sequence

Secondary structures

Function(s)

Cry1Aa

Cry3A

1.

Domain I

33-252

58-290

Seven a-helices

Pore formation

2.

Domain II

265-461

291-500

Three antiparallel 'b' sheets folded into three loops

Receptor binding and specificity determination

3.

Domain III

463-609

501-644

'b' sandwich of two antiparallel 'b' sheets

Receptor binding, Ion channel regulation and insect specificity