Homology modelling of dipteran specific Cry proteins of Bt Physicochemical and functional characterization, secondary structure prediction, model building and validation

Physico-chemical characterization of 4 cry proteins was done and interpreted the properties such as molecular weight, pI, EC, AI, GRAVY, amino acid composition and instability index. The highest GRAVY and AI value were found in Cry4Aa (0.827) and cry2Aa 1(84.53). Prediction of motifs, patterns, disulfide bridges and secondary structure, transmembrane regions and domains of Cry proteins were performed for functional characterization. Four template sequences (1I5P, ADL6, 2C9K and 1W99) were used for homology modeling (Swiss Model and EsyPred3D) to predict the 3D structure. The LG score for 1I5P, ADL6, 2C9K and 1W99 template shown in Swissmodel and EsyPred was extremely a good model. Active sites of the protein was determined by CASTp server and ranged from 83-239. The pocket area and volume ranged from 422.9 - 5828 and 518.1-3719.2, respectively. The validation for structure models was performed by using PROCHECK. The models were further checked with WHAT IF. Both the structures were analyzed using ProFunc tool which showed to have different functions as they had different structures and active sites. Thereby the structure plays a vital role in determining its function.