The metal ions Mg(2+) and Co(2+) are essential for life, although to different degree. They have similar chemical and physical properties, but their slight differences result in Mg(2+) to be the most abundant metal ion in living cells and the trace element Co(2+) being toxic at relatively low concentrations. Specialized transporters have evolved in living cells to supply and balance the Mg(2+) and Co(2+) need of the cells. The current knowledge of the molecular mechanisms of Mg(2+) and Co(2+) -specific transporters is very limited at this point. Recently, there has been remarkable advances to understand the CorA family, a family of transporters that are able to transport both ions. These new data have increased our insights in how Mg(2+) and Co(2+) are translocated across membranes. Presently, CorA is probably the best system to study the mechanisms of Mg(2+) and Co(2+) transport. This chapter discusses the mechanisms through which CorA selects, transports, and regulates the translocation of its substrate. In addition, we highlight the physical and chemical properties of the substrates, which are important parameters required for better understanding of the transporter action.
Copyright © 2012 Elsevier Inc. All rights reserved.