Conformational and antigenic properties of SRYD-containing peptide analogues of Leishmania gp63 adhesion site
(EN)
Sakarellos-Daitsiotis, M.
(EN)
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
(EL)
Sakarellos-Daitsiotis, M.
(EN)
The antigenicity and conformational properties of the Ser-erg-Tyr-Asp (SRYD) segment (252-255) of the major surface glycoprotein of Leishmania, gp63, which plays a key role in the parasite-macrophage attachment, are presented. It was found that the antibody recognition, using anti-IASRYDQL antibodies, of the SRYD-containing analogues, Ac-SRYD-NH2 (1), ANIASRYD-NH2 (2), Ac-SRYD (3), SRYD (4) and ANIASRYD (5), is rather similar. The structure of the SRYD moiety in analogues 1 and 2 is characterized by the presence of a type I beta-turn, stabilized by the formation of a hydrogen bonding between the C-terminal trans-carboxamide proton and the Arg-CO and an ionic bridge between arginine and aspartic acid side chains, while the conformation of compounds 3, 4 and 5 is stabilized by an ionic bridge between the arginine side chain and the C-terminal carboxylate group. A common structural motif involving the arginine side chain in an ionic interaction is identified in all the SRYD analogues, which may explain the observed similarities in the antibody recognition of the reported peptides.
(EN)
