1. Molecular mechanism of metalloenzymes relating to oxygen activations.
Oxygen is an important molecule for ATP synthesis, metabolism, cell defense, and so on. Many metalloenzymes are included in these biological processes. These metalloenzymes produce high-valent metal-oxo complexes as key reaction intermediates in their catalytic cycles. We are studying electronic structures and reactivity of these high-valent metal-oxo complexes to understand molecular mechanism of these metalloenzymes.
2. Molecular science of metalloenzymes in the nitrogen cycle.
Some soil bacteria use nitrogen compounds as electron acceptors for ATP synthesis under anaerobic conditions and forms the global nitrogen cycle. This nitrogen cycle is important to keep balance of nitrogen compounds on earth and catalyzed by metalloenzymes. We are studying reaction mechanisms and molecular mechanisms of metalloenzymes relating to the nitrogen cycle.
3. New NMR probes to study the active site of metalloenzymes.
Hydrogen bonding and electronic interactions to metal-bound molecules are essential to understand the molecular mechanism of metalloenzymes. We are developing new NMR probes that are sensitive to the hydrogen bonding and electronic interactions to metal-bound molecules.
4. Functional alteration of metalloenzymes.
To increase utility of metalloenzymes to chemical synthetic reactions, we are studying functional alteration of metalloenzymes. On the basis of molecular mechanism and active structures of mettaloenzymes, we are trying to alter function of metalloenzymes.
Structure of copper nitrite reductase (left) and its model complex (right)
- "Effect of a Tridentate Ligand on the Structure, Electronic Structure, and Reactivity of the Copper(I) Nitrite Complex: Role of the Conserved Three-Histidine Ligand Environment of the Type-2 Copper Site in Copper-Containing Nitrite Reductases" J. Am. Chem. Soc. 130, 6088-6098 (2008)
- "Activation Parameters for Cyclohexene Oxygenation by an Oxoiron(IV) Porphyrin -Cation Radical Complex: Entropy Control of an Allylic Hydroxylation Reaction" Inorg. Chem. 46, 6227-6229 (2007)
- "Spectroscopic Characterization of Reaction Intermediates in Nitrite Reduction of Copper(I) Nitrite Complex as a Reaction Model for Copper Nitrite Reductase" Angew. Chemie. Int. Ed. 45, 1089-1092 (2006)
- "13C and 15N NMR Studies of Iron-Bound Cyanides of Heme proteins and related model complexes: Sensitive Probe for Detecting Hydrogen Bonding Interactions at the Proximal and Distal Sides" Inorg. Chem. 45, 6816-6827 (2006)
- "Essential Amino Acid Residues Controlling the Unique Regioselectivity of Heme Oxygenase in Psudomonas aeruginosa" J. Am. Chem. Soc. 126, 4466-4467 (2004)