KINETIC-ANALYSIS OF SYNTHETIC ANALOGS OF LINEAR-EPITOPE PEPTIDES OF GLYCOPROTEIN-D OF HERPES-SIMPLEX VIRUS TYPE-1 BY SURFACE-PLASMON RESONANCE

The interaction between mAb A16 and glycoprorein D (gD) of herpes simp lex virus type 1 was analyzed by studying the kinetics of binding with a surface-plasmon-resonance biosensor. mAb A16 belongs to group VII a ntibodies, which recognize residues 11-19 of gD. In a previous study, three critical residues, 4sp13, Arg16 and Phe17, of this epitope were identified by screening a phage display library that contained a rando m 15-amino-acid insert with the antibody. The contribution to binding of these residues in the motif DXXRF was further analyzed by an amino- acid-replacement study of the epitope gD-(9-19)-peptide and of a gD-(9 -19)-peptide mimotope, previously obtained by screening the phage disp lay library. Amino acid residues of the motif were replaced by a neutr al amino acid residue, an amino acid residue with opposite charge and a corresponding D-amino acid residue. Kinetic parameters of peptide an alogues were determined with a surface plasmon-resonance biosensor. Th e kinetic parameters of the peptide analogues were compared with the k inetic parameters of the interaction between mAb A16 and the epitope g D-(9-19)-peptide. The minimal size of the gD epitope for mAb A16 was a lso determined in this study. The kinetic constants of the resulting g D-(11-17)-peptide were found to be similar to those of entire gD. The kinetic analysis precisely defined the epitope on gD for mAb A16 to re sidues 11-17, identified Arg16 as an essential residue and suggested t hat Asp13 and Phe17 are mainly involved in stabilization of the second ary structure of the peptide.