Aim: This study was designed
to develop peptide analogs of Infectious Bursal Disease (IBD) virus VP5 protein
segment having cell penetrating ability to improve their interaction with cargo
molecule (Nucleic acid) without affecting the backbone conformation.
Materials and Methods: IBDV VP5 protein segment designated as RATH peptide
were synthesized using solid phase peptide synthesis and their solution
conformation was elucidated using CD spectroscopy in polar (water) and apolar (TFE)
solvents. Cell penetrating ability of RATH-CONH2 was observed using FITC labeled
peptide internalization in to HeLa cells under fluorescent microscopy. The
efficacy of RATH analog interactions with nucleic acids was evaluated using FITC
labeled oligonucleotides by fluorescence spectroscopy and plasmid constructs in
gel retardation assay.
Results: CD spectra of RATH analogs in water and
apolar trifluroethanol (TFE) helped to compare their secondary structures which
were almost similar with dominant beta conformations suggesting successful
induction of positive charge in the analogs without affecting back bone
conformation of CPP designed. Cell penetrating ability of RATH CONH2 in HeLa
cell was more than 90%. The fluorescence spectroscopy and plasmid constructs in
gel retardation assay demonstrated successful interaction of amide analogs with
nucleic acid.
Conclusion: Intentional changes made in IBDV derived
peptide RATH COOH to RATH CONH2 did not showed major changes in backbone
conformation and such modifications may help to improve the cationic charge in
most CPPs to interact with nucleic acid.
Keywords: IBDV, conformationa
analysis, gel retardation assay, RATH, VP5 protein
