Coordination Chemistry of Bacterial Metal Transport and Sensing

The transition or d-block metal ions manganese, iron, cobalt, nickel, copper, zinc and to a more specialized degree molybdenum, tungsten, and vanadium have been shown to be important for biological systems. These metal ions are \nubiquitously found in nature, nearly exclusively as constituents of proteins.1 The unique properties of metal ions have been exploited by nature to perform a wide range of tasks. \nThese include roles as structural components of biomolecules, signaling molecules, and catalytic cofactors in reversible oxidation-reduction and hydrolytic reactions and in structural rearrangements of organic molecules and electrontransfer chemistry.1 Indeed, metal ions play critical roles in the cell that cannot be performed by any other entity and are therefore essential for all of life. However, an individual metal ion is capable of performing only one or a few of these functions but certainly not all; as a result, nature has evolved mechanisms to effectively distinguish one metal from another. The coordination chemistry of metal ion-protein complexes is fundamental to this biological discrimination \nand is largely the focus of this review.