Mutational study of a lytic polysaccharide monooxygenase from Myceliophthora thermophila (MtLPMO9F): Structural insights into substrate specificity and regioselectivity

Abstract

Lytic polysaccharide monooxygenases (LPMOs) are key enzymes for the biotechnological exploitation of lignocellulosic biomass, yet their efficient application depends on the in-depth understanding of their mechanism of action. Here, we describe the structural and mutational characterization of a C4-active LPMO from Myceliophthora thermophila, MtLPMO9F, that belongs to auxiliary activity family 9 (AA9). MtLPMO9F is active on cellulose, cello-oligosaccharides and xyloglucan. The crystal structure of MtLPMO9F catalytic domain, determined at 2.3 & Aring; resolution, revealed a double conformation for loop L3 with a potential implication in the formation of aglycon subsites. Product analysis of reactions with cello-oligosaccharides showed a prevalent -4 to +2 binding mode. Subsequent biochemical characterization of 4 MtLPMO9F point mutants further provided insights in LPMO structure-function relationships regarding both substrate binding and the role of second-coordination sphere residues.

Keywords

Lytic polysaccharide monooxygenase; Mutational study; Substrate specificity

Published in

International Journal of Biological Macromolecules
2025, volume: 288, article number: 138574
Publisher: ELSEVIER

SLU Authors

• Sandgren, Mats

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Biochemistry and Molecular Biology

Publication identifier

• DOI: https://doi.org/10.1016/j.ijbiomac.2024.138574

Permanent link to this page (URI)

https://res.slu.se/id/publ/140175