Bioinformatics analysis of four proteins of Leishmania donovani to guide epitopes vaccine design and drug targets selection.

Visceral leishmaniasis (VL) is a serious and widespread parasitic disease caused by Leishmania donovani complex. The threat of this fatal disease continues due to the lack of ideal drugs or vaccines. In this study, we selected Amastin, CaNA2, Kmp-11 and PDI proteins of Leishmania donovani for study, which are VL vaccine candidates or possible drug targets. Eleven bioinformatics tools were used to analyze different aspects of these proteins, including amino acid composition, topology, signal peptide, secondary structure, surface properties, phosphorylation sites and kinases, protein binding sites, 3D homology modeling, B cell epitopes, MHC class Ⅰ and Ⅱ epitopes and protein-protein interactions. Finally, the functionally related amino acid sites and dominant epitopes of these proteins were founded. Some possible relationships between protein structure, phosphorylation sites, protein binding sites and epitopes were also discovered. High flexibility and random coils regions of protein have a tendency to be phosphorylated, bind proteins and present epitopes. Since some phosphorylation sites and their kinases are involved in Leishmania invasion and survival in host cells, they may be potential drug targets. Bioinformatics analysis helps us better understand protein function and find dominant epitopes to guide drug design and vaccine development.