San Diego, Calif. – For snakes, spiders, and other venomous creatures, the "business end," or active part, of a toxin is the area on the surface of a protein that is most likely to undergo rapid evolution in response to environmental constraints, say researchers from Ben Gurion University in Israel. Understanding these evolutionary forces can help researchers predict which part of unstudied toxins will do damage, and may also aid in the design of novel synthetic proteins with tailored pharmaceutical properties.