Changing the Structural Context of a Functional β-Hairpin: SYNTHESIS AND CHARACTERIZATION OF A CHIMERA CONTAINING THE CURAREMIMETIC LOOP OF A SNAKE TOXIN IN THE SCORPION α/β SCAFFOLD (∗)

摘要: An approach to obtain new active proteins is the incorporation of all or a part well defined site onto natural structure acting as structural scaffold. According this strategy we tentatively engineered curaremimetic molecule by transferring functional central loop snake toxin, sequence 26-37, sandwiched between two hairpins, structurally similar β-hairpin scorpion toxin charybdotoxin, stabilized short helix. The resulting chimeric molecule, only 31 amino acids long, was produced solid phase synthesis, refolded, and purified homogeneity. As shown analysis performed CD NMR spectroscopy, chimera maintained expected α/β fold characteristic toxins presented remarkable stability. competitively displaces α from acetylcholine receptor at 10-5M concentrations. Antibodies, elicited in rabbits against chimera, recognize parent prevent its binding receptor, thus neutralizing toxic function. All these data demonstrate that transfer charybdotoxin scaffold has general applications engineering novel ligands for membrane receptors vaccine design.