Cadmium-zinc exchange and their binary relationship in the structure of Zn-related proteins: a mini review.

Research on cadmium-zinc exchange in proteins is important for understanding one of the main sources of Cd's biological toxicity. Because of the similar properties of these two elements, most living organisms must prevent Cd from replacing Zn in Zn-requiring proteins in order for those proteins to function normally. Recent structural studies of a variety of proteins associated with the versatile physiological functions of Zn have revealed widespread instances of Cd-Zn exchange in proteins of a large number of living organisms. Ongoing work is focused on discovering the structural mechanisms of Cd-Zn exchange and the potentially diverse roles of Cd at Zn functional sites in proteins. This research is a prerequisite to understanding the evolution of Cd-tolerant species (e.g., Cd hyperaccumulating plants) and to the engineering of optimal strategies for protecting the public heath against Cd pollution.