Biology Department Seminar

Metal transporters use unique coordination chemistry to move metal ions across the membrane. The metallochemistry of metal transporters is fundamentally distinct from that of metalloenzymes where metal ions are bound tightly as integral parts of the protein structures. Metal transporters selectively bind metal ions and translocate them against concentration gradients. The binding affinity of metal transporters is much lower than expected for equilibrium metal binding in cells, while the timescale of metal transport is millisecond, vastly faster than many metalloproteins that typically take hours to release bound metal ions. The current conceptual framework of metallochemistry is inadequate to explain how metal transporters acquire metal ions against thermodynamic gradients while maintaining rapid metal mobility, yet extraordinary selectivity over similar metal ions. Therefore, metal transporters provide a unique research opportunity for making paradigm-shifting discoveries at the interface of biochemistry and metallochemistry. I will present the structure of a zinc transporter YiiP and discuss how zinc coordination chemistry is tailored to distinct functions in a membrane transporter.