Computer-aided analysis of structural properties and epitopes of Iranian HPV-16 E7 oncoprotein

Infection by human papillomavirus type 16 (HPV-16) is the cause of 50% or more of cervical cancers in women. The E7 oncoprotein of HPV-16 has long been known as a potent immortalizing and transforming agent. We used different servers like PseAAC, MHC_binding, MHC_II_binding and Expasy for the present computational prediction. The results for T cell epitopes showed that B1501, A0203, A0201, A0202, A6801 and DRB0405 alleles had lower IC50 than other alleles. We also predicted several peptides with the best binding affinities for alleles of the most frequent MHC class I and II alleles of the various ethnic groups living in the different region of Iran. Two peptides (26-35) and (44-52) were predicted as B-cell epitopes. According to this analysis 1 N-glycosylation site, 2 PKC sites, 4 CK2 sites and 3 disulfide sites were predicted. Our computational study predicted that B cell epitope 1 was Casein kinase II phosphorylated (site No. 31) and glycosylated (site No. 29). Putative MHC-I epitopes 3 and 5 and MHC-II epitopes 19, 21 and 26 were predicted to be casein kinase II phosphorylated. MHC-II epitopes 19 and 21 was predicted to be glycosylated. T cell epitopes 1, 13, 16 and 24 were demonstrated to be kinase C phosphorylated. The result of this analysis for Iranian HPV-16 E7 also indicated that 21.43%, 18.37% and 60.20% of the protein were in the α-helix, extended strand and random coil respectively.