Abstract

Background

Molecular Mechanics (MM) is the method of choice for computational studies of biomolecular systems owing to its modest computational cost, which makes it possible to routinely perform molecular dynamics (MD) simulations on chemical systems of biophysical and biomedical relevance. Vitiligo is a skin disorder characterized by selective melanocyte destruction and concomitant appearance of depigmented macules that over time enlarge, coalesce, and form patches. It has been suggested that vitiligo is, at least in part, caused by autoimmune responses mediated by cytotoxic T cells against melanocytes, causing depigmentation Immune responses contribute to the pathogenesis of vitiligo and target melanoma sometimes associated with vitiligo-like depigmentation in some melanoma patients. It has been perviously reported that the tyrosinase autoantigen was immunorecognized with the same molecular pattern by sera from vitiligo and melanoma patients. Five autoantigen peptides was found to compose the immunodominant antityrosinase response: aa95-104FMGFNCGNCK; aa175-182 LFVWMHYY; aa176-190FVWMHYYVSMDALLG; aa222-236IQKLTGDENFTIPYW, and aa233-247IPYWDWRDAEKCDIC. Synergistic therapies for the treatment of vitiligo are provided. The major therapies for the treatment of vitiligo a pigmentary disorder characterized by patchy depigmentation of skin are Psoralens plus UV-A, steroids, basic fibroblast growth factor (bFGF) peptide location or surgical procedures. Psoralens plus UV-A is effective in about 50% of cases, steroids are limitedly effective only in fast spreading cases of vitiligo and often reoccurs on stoppage of treatment. Surgical treatment is the last resort for vitiligo therapy, when all other therapies failed. It is limitedly effective. Basic fibroblast growth factor peptide(s) location was developed as a new mode therapy for the treatment of vitiligo. Therefore, SEQ ID NO: 01 VPHIPPN, SEQ ID NO: 02 MPPTQVS, SEQ ID NO: 03 QMHPWPP, SEQ ID NO: 1 1 LPLTPLP, SEQ ID NO: 12 QLNVNHQARADQ, SEQ ID NO: 13 TSASTRPELHYP, SEQ ID NO: 14 TFLPHQMHPWPP peptides, modified peptides and antibody or antibody fragments inhibiting the activity of MIA and can be used for treating vitiligo by inducing re-pigmentation. Fragment-based lead discovery is a method used for finding lead compounds as part of the drug discovery process.

Scope of Review

As one of the main factors limiting the accuracy of MD results is the empirical force field used, the present paper offers a review of recent developments in the CHARMM additive force field, one of the most popular bimolecular force fields. Additionally, we present a detailed discussion of the CHARMM Drude polarizable force field, anticipating a growth in the importance and utilization of polarizable force fields in the near future. Throughout the discussion emphasis is placed on the force fields’ parametrization philosophy and methodology. In this science project we perfomed an in silico ChemoProteomic Prediction-Scan for the generation of Antigenic PatternLFA-3/IgG fusion polypeptide aa95-104FMGFNCGNCK; aa175-182 LFVWMHYY; aa176-190FVWMHYYVSMDALLG; aa222-236IQKLTGDENFTIPYW, and aa233-247IPYWDWRDAEKCDICmimetic pharmacophore on conserved Vitiligo post-trancripts domains.

Major Conclusions

Recent improvements in the CHARMM additive force field are mostly related to newly found weaknesses in the previous generation of additive force fields. Beyond the additive approximation is the newly available CHARMM Drude polarizable force field, which allows for MD simulations of up to 1 microsecond on CHARMM additive and polarizable force fields for biophysics and computer-aided drug design analysis as an in silico chemoproteomic prediction-scan for the generation of a tyrosinase aa95-104FMGFNCGNCK antigenic pattern LFA-3/IgG fusion polypeptide IleAlaArgArgPheLeuOH (Kinetensin) mimetic pharmacophore on conserved Vitiligo post-trancripts domains.

General Significance

Addressing the limitations ensures the reliability of the new CHARMM36 additive force field for the types of calculations that are presently coming into routine computational reach while the availability of the Drude polarizable force fields offers a model that is an inherently more accurate model of the underlying physical forces driving macromolecular structures and dynamics.

Keywords

CHARMM additives; polarizable force fields; biophysics; computer-aided drug design; in silico; chemoproteomic; prediction-scan; tyrosinase; aa95-104FMGFNCGNCK antigenic pattern; LFA-3/IgG fusion polypeptide; IleAlaArgArgPheLeuOH (Kinetensin); mimetic; pharmacophore; conserved Vitiligo post-trancripts domains; CHARMM additive and polarizable force fields for biophysics and computer-aided drug design; molecular dynamics, empirical force field, potential energy function, molecular mechanics, computer-aided drug design, biophysics.