Crystal structures of the endonuclease domain of Lymphocytic choriomeningitis virus (LCMV) in complex with two diketo-acid (DKA) compounds were determined. Based on these data and activity assays, two new DKAs with good affinity for the LCMV endonuclease domain were synthesized.

In bacteria, high-affinity zinc import is accomplished by ATP-binding cassette (ABC) transporters, which rely on extracellular solute-binding proteins (SBPs) to acquire the metal and deliver it to the membrane permease. The crystal structure of the zinc-bound (holo) form of Citrobacter koseri SBP ZnuA has been determined. Despite 95% sequence identity to the ZnuA homologue from Salmonella enterica, C. koseri ZnuA exhibits different zinc-coordination and a closed rather than open conformation. Comparison with other close ZnuA homologue structures suggests a flexible conformational landscape that may be important for zinc binding and/or delivery to the permease.