Binuclear non-heme iron enzymes are found in numerous aerobic organisms and perform a wide variety of different chemistries often involving O2 activation. Their reactions include H-atom abstraction, desaturation, hydroxylation, electrophilic aromatic substitution and reduction of O2 to H2O. The ligand set of these enzymes exhibit mostly His and carboxylate ligands, but differ for different reactions that the enzyme performs. During their reaction cycle they can exhibit distinguished intermediate states based on their iron oxidation state and their ligand set.We have employed circular dichroism (CD), magnetic circular dichroism (MCD) and variable temperature variable field MCD (VTVH MCD) to elucidate the mechanistic strategies for the O2 binding in three enzymes. In combination with density functional theory (DFT) we employed nuclear resonant vibrational spectroscopy (NRVS), which allow to selectively observe the vibrations that involve the iron centers.Enzymes to be considered are aldehyde decarbonylase (ADO), the amino acid �-hydroxylase (CmlA) and a native iron bearing urease (UR). These enzymes differ both in their number of His ligands (2, 3 and 4) as well as in their number of Glu/Asp ligands (4, 3 and 2) and make them an ideal target to address how differences in their structure correlate with their diverse functions.

Structure/function relations in binuclear non-heme iron enzymes

248th National Meeting (2014)

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