Recent insights into lytic polysaccharide monooxygenases (LPMOs)

Area of Science:

• Biochemistry
• Structural Biology
• Enzymology

Background:

• Lytic polysaccharide monooxygenases (LPMOs) are copper enzymes vital for degrading recalcitrant polysaccharides.
• They play key roles in natural carbon cycling and are utilized in the biorefinery industry.
• Recent discoveries include new LPMO families (AA14 and AA15) with unique characteristics.

Purpose of the Study:

• To structurally characterize novel LPMO families AA14 and AA15.
• To investigate the mechanistic pathways and substrate interactions of LPMOs.
• To explore the presence of LPMOs in the animal kingdom.

Main Methods:

• Neutron crystallography and high-resolution X-ray crystallography were employed to determine LPMO structures.
• Computational and experimental studies were conducted to analyze LPMO mechanisms.
• Biochemical assays were used to investigate substrate degradation and cofactor requirements.

Main Results:

• Two new LPMO families, AA14 and AA15, were structurally characterized.
• AA14 LPMOs exhibit xylan degradation on complex substrates, while AA15 LPMOs expand LPMO presence to animals.
• Structural data suggest the presence of specific oxygen species at the active site.
• Evidence indicates LPMOs can act as monooxygenases or peroxygenases depending on conditions.

Conclusions:

• The discovery of AA14 and AA15 families broadens the known diversity and ecological roles of LPMOs.
• Structural and mechanistic insights advance our understanding of LPMO function in various biological systems.
• LPMOs exhibit mechanistic flexibility, adapting their function based on substrates and co-substrates.