Synthesis and evaluation of antigenic properties of peptides of the HIV-1 protein gp 41

Scheme is described for the synthesis of 19- and 21-member peptides which constitute a part of the domain (sequence 584-609) from the conservative region of the transmembrane protein gp 41 HIV-1. The synthesis was carried out using standard methods of peptide chemistry in solution. The peptides were built from fragments which were synthesized by means of stepwise joining of amino acid residues starting from the C-terminus, using activated esters. The "complex F" or DCC + HONB methods were employed for condensation of the fragments. Alpha amino groups were protected by means of Z- and Boc- protecting groups. The tert. butyl group was used for the protection of functional side chains. The sulfhydryl group of cysteine was blocked with S-acetamidomethyl group and salt formation or benzyl esters were used for protection of the carbonyl group. During the synthesis, it was necessary to solve problems connected with racemization of Asp and Glu residues in the course of condensation of fragments, as well as formation of a beta-peptide at the position of aspartic acid. HPLC and NMR methods were utilized extensively for the separation and characterization of the structure of the synthesized compounds. The final peptides were tested in enzyme immunoassay. ELISA tests proved that the peptides can be employed as antigenic components for the diagnosis of HIV-1.