Structural diversity of lytic polysaccharide monooxygenases

Area of Science:

• Biochemistry
• Enzymology
• Biotechnology

Background:

• Lytic polysaccharide monooxygenases (LPMOs) are copper-containing enzymes that cleave glycosidic bonds in polysaccharides.
• They are crucial for biomass degradation and have potential in industrial enzyme cocktails.
• LPMOs exhibit significant diversity in sequence, modular structure, and substrate specificity, acting on cellulose, chitin, starch, and various hemicelluloses.

Purpose of the Study:

• To review recent structural insights into LPMOs.
• To highlight the diversity of substrate-binding surfaces among LPMOs.
• To discuss the implications of structural data for enzyme engineering and biomass processing.

Main Methods:

• Review of recently published LPMO structures.
• Analysis of LPMO sequence and modular diversity.
• Examination of the catalytic histidine brace motif and substrate-binding surface residues.
• Inclusion of the first reported enzyme-substrate complex structure.

Main Results:

• LPMOs possess a conserved catalytic histidine brace motif for copper binding.
• Significant variations exist in the residues and their arrangement on the substrate-binding surface.
• Recent structural data, including an enzyme-substrate complex, provide detailed insights into LPMO mechanisms.
• The diversity in surface structures correlates with varied substrate specificities.

Conclusions:

• Structural studies are rapidly expanding our understanding of LPMO function.
• The diverse substrate-binding surfaces of LPMOs are key to their varied activities.
• These insights are critical for designing tailored LPMOs for efficient biomass conversion in industrial settings.