Pharmaceutica Analytica Acta

Abstract

Conformation of the Antigenic Peptide Tyrosinase (192-200) in Water and DMSO-d6 by NMR Spectroscopy and MD Simulations

Evans C Coutinho, Mishra NB, Deep Bhattacharya, Sudha Srivastava, Mamata Joshi and Mushtaque Shaikh

Melanomas represent the most resistant form of cancer. If detected early, a cure is possible with the conventional therapies, while metastatic forms are almost resistant to conventional therapies. A new area i.e. immune based therapy shows promise of cytolytic activity against tumor cells. Production of antibodies against the antigenic epitopes present in the melanoma is the main basis of this immune based therapy. Production of T cell response against the tumor cells has been seen by synthetic antigenic epitopes. The antigenic nonameric peptide epitope of tyrosinase (192-200) with the sequence S1EIWR5DIDF9 causes significant induction of the T cell response in melanoma patients. In realm of the significance of this peptide, a solution state NMR structure of 192-200 amino acid section of tyrosinase has been investigated, to assimilate the relationship between the antigenicity and the conformation of the peptide. NMR studies were carried out in H2O:D2O (95:5) and DMSO-d6 solvents. Molecular dynamics simulations with NMR constraints were carried out using the GROMACS v .4.6.5 package. The results suggest the prevalence of a β-sheet structure both in H2O as well as in DMSO-d6.