Potential-energy calculations of terminally blocked tetrapeptides from the third loop of short-chain snake venom neurotoxins.

The conformational space of six tetrapeptides from the beta-bends in the third loop of short-chain snake venom neurotoxins was investigated with the aid of energy calculations. It was shown that these peptides can be divided into two groups: those with a specific preference for an alpha-helix and those that exist as an ensemble of beta-turn conformations.