| Description |
This study describes a method for bacterial expression and purification of previously uncharacterized proteins. The proteins chosen for this study come from auger snail toxins, which have evolved to help the snail hunt and kill their prey. Evolutionary pressure between predator and prey selects for diverse toxin proteins with new functions. New functions could be accomplished by repurposing pre-existing proteins within the snail to become toxins or by developing completely new proteins, potentially with novel folded structures. Well over 10,000 known species of venomous marine snails, each with distinct toxins containing hundreds of protein components, represent a rich source of potentially novel protein folds (Olivera et al. 2014). However, toxin proteins are difficult to harvest from small snails and challenging to chemically synthesize if larger than ~35 residues. Overexpression of toxin protein genes in bacteria allows for large amounts of folded, functional protein, without predicted limitations on size. This study selected five auger snail toxins, augertoxins, for expression and purification. The augertoxins ranged in size from 40 residues to 150 residues for the mature toxin. Four of five chosen toxins were expressed successfully, and one of those was further purified to give pure, testable toxin protein. Future work will further characterize pure protein using x-ray crystallography to determine the folded structure and biological assays to explore relevant functions. My foundational work on an optimal bacterial expression system can be applied to other uncharacterized toxin proteins and will help the search for new folds and functions. |
