Abstract
Purpose: :
We have generated six 12–mer peptide candidates using phage display technology (random, 12–mer phage display peptide library, New England Biolabs) by sequential screening for peptides that bind directly to purified HSV–1 glycoprotein D (gD–1) and cell expressed native forms of gD–1 to unravel preserved epitopes that have crucial structural–functional activity in HSV–1 entry.
Methods: :
After removal of non–specific phages, plaque purification, DNA isolation and nucleotide sequencing our screens yielded a final of six peptide candidates with gD–1 binding ability by ELISA and blocking of HSV–1 entry by co–incubation.
Results: :
Previous studies on gD–1 showed functionally important regions that neutralize virus infectivity when these sites are exposed to specific antibodies or mutated. The backbone of –Glu–Thr–Val–Glu–Ser–Cys–Leu–Ala–Lys– repetitive in the synthetic peptides generated, suggest interactions between the ligand and co–receptor that are close, physical and multifunctional, possibly harnessing other co–ligands ensuring virus infection. The aliphatic residues infer a higher structural than charge activity in the mechanism of entry.
Conclusions: :
Taken together we propose a low degree of conformational change limited by close physical interactions between HSV–1 gD and its co– receptors; nectin–1, HVEM and 3OS–HS.
Keywords: herpes simplex virus • glycoconjugates/glycoproteins • receptors