Homology modeling deduced 3D structure of the <i>Cry</i>1Ab22 toxin

Abstract

<img src='/image/spc_char/delta1.gif' border=0>-Endotoxin<i> Cry</i>1Ab22 is produced by <i>Bacillus thuringiensis</i> BtS2491Ab. The toxic spectrum of this protein is reported to span Lepidopteron and Dipteran. Here, we predict the theoretical structural model of newly reported <i>Cry</i>1Ab22 toxin by homology modeling method on the structure of the <i>Cry</i>1Aa toxin. Proposed model resembles the target by sharing common three dimensional, three domain structure. The main differences being located in the length of loops, absence of helixes (<img src='/image/spc_char/alpha.gif' border=0>7b, <img src='/image/spc_char/alpha.gif' border=0>10a,<img src='/image/spc_char/alpha.gif' border=0> 10b,<img src='/image/spc_char/alpha.gif' border=0>11a) and presence of additional components <img src='/image/spc_char/beta.gif' border=0>21, <img src='/image/spc_char/alpha.gif' border=0>9b). Few of the components like <img src='/image/spc_char/alpha.gif' border=0>9a,<img src='/image/spc_char/alpha.gif' border=0>9b and <img src='/image/spc_char/alpha.gif' border=0> 12a are positioned spatially at different locations. A better understanding of the 3D structure will be helpful in designing the domain swapping and mutagenesis experiments aimed at improving toxicity, and will lead to a deeper understanding of the common mechanism of toxins.