Enzymology
Comparison of three seemingly similar lytic polysaccharide monooxygenases from Neurospora crassa suggests different roles in plant biomass degradation
Many fungi produce multiple lytic polysaccharide monooxygenases (LPMOs) with seemingly similar functions, but the biological reason for this multiplicity remains unknown. To address this question, here we carried out comparative structural and functional characterizations of three cellulose-active C4-oxidizing family AA9 LPMOs from the fungus Neurospora crassa, NcLPMO9A (NCU02240), NcLPMO9C (NCU02916), and NcLPMO9D (NCU01050). We solved the three-dimensional structure of copper-bound NcLPMO9A at 1.6-Å resolution and found that NcLPMO9A and NcLPMO9C, containing a CBM1 carbohydrate-binding module, bind cellulose more strongly and were less susceptible to inactivation than NcLPMO9D, which lacks a CBM.Structural and Functional Characterization of a Lytic Polysaccharide Monooxygenase with Broad Substrate Specificity
Background: The recently discovered lytic polysaccharide monooxygenases (LPMOs) are important in enzymatic conversion of lignocellulosic biomass.Results: We describe structural and functional studies of NcLPMO9C, which cleaves both cellulose and certain hemicelluloses.Conclusion: NcLPMO9C has structural and functional features that correlate with the enzyme's catalytic capabilities.Significance: This study shows how LPMO active sites are tailored to varying functionalities and adds to a growing LPMO knowledge base.
