Differences in secondary structure of HAV-synthetic peptides induced by the sequential order of T- and B-cell epitopes

The present study was undertaken to examine the structural features of two peptide constructs designed on the basis of linear combination of B and T-c ell epitopes in different orientations (BT and TB) that may be important to explain the differences in the elicited antihepatitis A virus immune respo nse and in the interaction with biological model membranes. A CD study was carried out and the corresponding quantitative analysis of the experimental data was done using deconvolution computer programs. Moreover, fluorescenc e experiments were performed to analyze differences in the fluorescence emi ssion spectra of both molecules. The main conformational difference by CD s tudies was obtained working in aqueous medium. Although the TB sequence ado pted a preferably random coil structure, the BT peptide was best fitted wit h beta -type structures. These results are further supported by fluorescenc e studies. These finding have relevance for the design of synthetic immunop eptides. (C) 2001 John Wiley & Sons, Inc.