Many metalloenzymes and metal-activated enzymes utilize cis or fac coordination sites on the metal to bind substrate and effect catalytic transformations.  For example, oxalate oxidases and oxalate decarboxylases contain manganese bound to three facial histidine residues, one glutamate, and two cis water molecules.  The coordinated water molecules are likely displaced by substrates during catalysis.  To structurally model the active sites of such enzymes, research with undergraduates in my laboratory, and in collaboration with the Pecoraro laboratory at the University of Michigan, has focused on the synthesis of several N3O and N2O multidentate ligands, with the goal of achieving adjacent coordination sites bound by exchangeable solvent molecules. Metal complexes of 1,4,7-triazacyclononane-1-acetate, 1,4-diisopropyl-1,4,7-triazacyclononane-1-acetate, and N,N-bis(3,5-dimethylpyrazolyl methyl)glycinate were synthesized.  The complexes were characterized by x-ray crystallography and other methods. Applications of these complexes to modeling the active sites of manganese oxalate-degrading enzymes and the CO2-fixing magnesium activated enzyme, rubsico, will be discussed.

Synthetic N<sub>3</sub>O and N<sub>2</sub>O ligand complexes as
potential enzyme models

241st National Meeting (2011)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Synthetic N3O and N2O ligand complexes as potential enzyme models

Synthetic N₃O and N₂O ligand complexes as potential enzyme models