Lytic Polysaccharide Monooxygenase from <i>Talaromyces amestolkiae</i> with an Enigmatic Linker-like Region: The Role of This Enzyme on Cellulose Saccharification

Lytic Polysaccharide Monooxygenase from <i>Talaromyces amestolkiae</i> with an Enigmatic Linker-like Region: The Role of This Enzyme on Cellulose Saccharification

The first lytic polysaccharide monooxygenase (LPMO) detected in the genome of the widespread ascomycete <i>Talaromyces amestolkiae</i> (TamAA9A) has been successfully expressed in <i>Pichia pastoris</i> and characterized. Molecular modeling of TamAA9A showed a structure simil...

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Bibliographic Details
Main Authors: Juan Antonio Méndez-Líter, Iván Ayuso-Fernández, Florian Csarman, Laura Isabel de Eugenio, Noa Míguez, Francisco J. Plou, Alicia Prieto, Roland Ludwig, María Jesús Martínez
Format: Article
Language:English
Published: MDPI AG 2021-12-01
Series:International Journal of Molecular Sciences
Subjects:
LPMO
wheat straw
brewers spent grain
saccharification
AA9
oxidative biomass degradation
Online Access:https://www.mdpi.com/1422-0067/22/24/13611
Description
Summary:The first lytic polysaccharide monooxygenase (LPMO) detected in the genome of the widespread ascomycete <i>Talaromyces amestolkiae</i> (TamAA9A) has been successfully expressed in <i>Pichia pastoris</i> and characterized. Molecular modeling of TamAA9A showed a structure similar to those from other AA9 LPMOs. Although fungal LPMOs belonging to the genera <i>Penicillium</i> or <i>Talaromyces</i> have not been analyzed in terms of regioselectivity, phylogenetic analyses suggested C1/C4 oxidation which was confirmed by HPAEC. To ascertain the function of a C-terminal linker-like region present in the wild-type sequence of the LPMO, two variants of the wild-type enzyme, one without this sequence and one with an additional C-terminal carbohydrate binding domain (CBM), were designed. The three enzymes (native, without linker and chimeric variant with a CBM) were purified in two chromatographic steps and were thermostable and active in the presence of H<sub>2</sub>O<sub>2</sub>. The transition midpoint temperature of the wild-type LPMO (Tm = 67.7 °C) and its variant with only the catalytic domain (Tm = 67.6 °C) showed the highest thermostability, whereas the presence of a CBM reduced it (Tm = 57.8 °C) and indicates an adverse effect on the enzyme structure. Besides, the potential of the different <i>T. amestolkiae</i> LPMO variants for their application in the saccharification of cellulosic and lignocellulosic materials was corroborated.
ISSN:1661-6596
1422-0067

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