FIG. 1.

Crude extracts of M13 clones digested with trypsin were electrophoresed in an 10% SDS–polyacrylamide gel and transferred to an Immobilon-P membrane for immunoblotting with the Cry1Ac1 antibody. Lane 1, molecular mass standards; lane 2, wild-type M13 crude extract; lane 3, wild-type M13 crude extract, trypsin treated; lane 4, Q₁₃₃R M13 crude extract; lane 5, Q₁₃₃R M13 crude extract, trypsin treated; lane 6, I₁₃₂S M13 crude extract; lane 7, I₁₃₂S M13 crude extract, trypsin treated; lane 8, I₁₃₂L M13 crude extract; lane 9, I₁₃₂L M13 crude extract, trypsin treated. All other nontoxic helix α4 mutants were also stable to trypsin digestion (data not shown).