The aim of this project is to develop a stable in vitro model for the active site of zinc-based proteins. The zinc raft motif in particular, involving the coordination of a zinc ion by adjacent β-strand residues, has been identified in a sampling of PDB structures to include catalytic, structural, regulatory, and substrate activity. The zinc raft motif relies significantly on the coordination of histidine residues. In this research, synthesis of a Zn2+model was conducted using 4-methylimidazole as a structural analog to histidine. Trials yielded a stable model with Zn2+ exhibiting a coordination number of four, which is found in structural and regulatory raft motifs. Furthermore, investigations into suitable counter-ions revealed that ClO4- anions readily crystallize these [Zn(4-MeIm)4] 2+ complexes without exchanging for 4-methylimidazole ligands or increasing the coordination number of Zn2+ beyond four. 1H NMR, IR, and UV-VIS spectroscopy, along with elemental analysis, were employed to determine the structure of this [Zn(4-MeIm)4](ClO4)2 model. A Co2+ analog was also synthesized, and these molecular models serve as potential alternatives to purified protein samples in biological testing.

Creating a Zn2+/Co2+model for study of biologically relevant zinc clusters

ACS Spring Meeting 2021

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