Production and Purification of Recombinant Toxins.

Recombinant expression of toxins enables us to produce adequate quantities of these proteins which can be used to perform experiments at molecular, cellular, and behavioral levels. Furthermore, toxins can be edited by using simple molecular biology methods when producing them recombinantly. Thus, in many cases establishing a protocol for the recombinant expression of a toxin of interest is crucial in exploring the structure and function of the toxin and its effectors. To date, Escherichia coli (E. coli) represents the most widely used heterologous expression system in which recombinant proteins are usually accumulated in the bacterium cytoplasm. However, as many animal toxins contain disulfide bonds they tend to be misfolded and aggregate when found in the reducing E. coli cytoplasm. In contrast, conditions in the bacterium periplasm allow disulfide bond formation and correct folding of such toxins. Here, we describe a protocol for the production and purification of bioactive recombinant disulfide-rich toxins via periplasmic expression.