A novel amyloid designable scaffold and potential inhibitor inspired by GAIIG of amyloid beta and the HIV-1 V3 loop.

The GAIIG sequence, common to the amyloid beta peptide (residues 29-33) and to the HIV-1 gp120 (residues 24-28 in a typical V3 loop), self-assembles into amyloid fibrils, as suggested by theory and the experiments presented here. The longer YATGAIIGNII sequence from the V3 loop also self-assembles into amyloid fibrils, of which the first three and the last two residues are outside the amyloid GAIIG core. We postulate that this sequence, with suitably selected modifications at the flexible positions, can serve as a designable scaffold for novel amyloid-based materials. Moreover, we report the single crystal X-ray structure of the beta-breaker peptide GAIPIG at 1.05 Å resolution. The structural information provided in this study could serve as the basis for structure-based design of potential inhibitors of amyloid formation.