Artificial Metalloenzymes as Catalysts for Oxidative Lignin Degradation
We report novel artificial metalloenzymes (ArMs), containing tris(pyridylmethyl)amine (TPA), for the atom economic oxidation of lignin β-O-4 model compounds, using hydrogen peroxide. The protein scaffold alters the selectivity of the reaction from a low yielding cleavage reaction when using the parent Fe-tpa complex to a high yielding benzylic alcohol oxidation when using the complex incorporated into a protein scaffold, SCP-2L A100C. Engineering the protein scaffold to incorporate glutamic acid was found to improve the ArM activity, showing that rational design of the protein environment using metal binding amino acids can be a first step toward improving the overall activity of an artificial metalloenzyme.
Metal: FeLigand type: Tris(pyridylmethyl)amine (TPA)Host protein: Steroid Carrier Protein 2L (SCP 2L)Anchoring strategy: Cystein-maleimideOptimization: Chemical & geneticReaction: Lignin oxidationMax TON: 20ee: ---PDB: ---Notes: Reaction performed with a lignin model compound and hydrogen peroxide as oxidizing agent