Copper Complexes as Bioinspired Models for Lytic Polysaccharide Monooxygenases.

Area of Science:

• Biochemistry
• Bioinorganic Chemistry
• Enzymology

Background:

• Lytic polysaccharide monooxygenases (LPMOs) are copper-containing enzymes crucial for degrading recalcitrant polysaccharides.
• Understanding LPMO mechanisms is vital for biotechnological applications in biomass conversion.
• Functional models are needed to elucidate the intricate catalytic cycles of these enzymes.

Purpose of the Study:

• To synthesize and characterize novel mononuclear copper complexes as functional models of LPMOs.
• To investigate the catalytic activity of these models in the oxidative cleavage of polysaccharides.
• To identify key reactive intermediates formed during the enzymatic reaction.

Main Methods:

• Synthesis of two distinct mononuclear copper complexes.
• Spectroscopic characterization (e.g., UV-Vis, EPR) to determine structural and electronic properties.
• Enzymatic assays using p-nitrophenyl-β-d-glucopyranoside as a model substrate.
• Reaction monitoring to detect and identify intermediates.

Main Results:

• The synthesized copper complexes exhibit structural and spectroscopic similarities to native LPMOs.
• Both complexes demonstrate catalytic activity in the oxidative cleavage of the model substrate.
• A highly stable copper(II) hydroperoxide intermediate was successfully detected under reaction conditions.

Conclusions:

• The developed copper complexes serve as effective functional models for LPMOs.
• These models provide valuable insights into the catalytic mechanism, particularly the role of copper-oxygen species.
• The detection of the copper(II) hydroperoxide intermediate advances the understanding of LPMO reactivity.