Crystal structures of AztD provide mechanistic insights into direct zinc transfer between proteins.

Zinc acquisition from limited environments is critical for bacterial survival and pathogenesis. AztD has been identified as a periplasmic or cell surface zinc-binding protein in numerous bacterial species. In , AztD can transfer zinc directly to AztC, the solute binding protein for a zinc-specific ATP-binding cassette transporter system, suggesting a role in zinc acquisition and homeostasis.

Mechanisms of zinc binding to the solute-binding protein AztC and transfer from the metallochaperone AztD.

Bacteria can acquire the essential metal zinc from extremely zinc-limited environments by using ATP-binding cassette (ABC) transporters. These transporters are critical virulence factors, relying on specific and high-affinity binding of zinc by a periplasmic solute-binding protein (SBP). As such, the mechanisms of zinc binding and release among bacterial SBPs are of considerable interest as antibacterial drug targets.