Research into the Bioengineering of a Novel alpha-Conotoxin from the Milked Venom of Conus obscurus

The marine cone snail produces one of the fastest prey strikes in the animal kingdom. It injects highly efficacious venom, often causing prey paralysis and death within seconds. Each snail has hundreds of conotoxins, which serve as a source for discovering and utilizing novel analgesic peptide therapeutics. In this study, we discovered, isolated, and synthesized a novel alpha 3/5-conotoxins derived from the milked venom of Conus obscurus (alpha-conotoxin OI) and identified the presence of alpha-conotoxin SI-like sequence previously found in the venom of Conus striatus. Five synthetic analogs of the native alpha-conotoxin OI were generated. These analogs incorporated single residue or double residue mutations. Three synthetic post-translational modifications (PTMs) were synthetically incorporated into these analogs: N-terminal truncation, proline hydroxylation, and tryptophan bromination. The native alpha-conotoxin OI demonstrated nanomolar potency in Poecilia reticulata and Homo sapiens muscle-type nicotinic acetylcholine receptor (nAChR) isoforms. Moreover, the synthetic alpha-[P9K] conotoxin OI displayed enhanced potency in both bioassays, ranging from a 2.85 (LD50) to 18.4 (IC50) fold increase in comparative bioactivity. The successful incorporation of PTMs, with retention of both potency and nAChR isoform selectivity, ultimately pushes new boundaries of peptide bioengineering and the generation of novel alpha-conotoxin-like sequences.