Lpmo

Lytic polysaccharide monooxygenases (LPMOs) oxidatively depolymerize recalcitrant polysaccharides, which is important for biomass conversion. The catalytic domains of many LPMOs are linked to carbohydrate-binding modules (CBMs) through flexible linkers, but the function of these CBMs in LPMO catalysis is not well understood. In this study, we utilized MtLPMO9L and MtLPMO9G derived from Myceliophthora thermophila to investigate the impact of CBMs on LPMO activity, with particular emphasis on their influence on H2 O2 tolerance...

Degradation of polysaccharides based on lytic polysaccharide monooxygenases (LPMOs) has received considerably interest in the environment and energy fields since 2010. With the rapid development of nanozymes in various fields, it is highly desirable but challenging to develop LPMO-like nanozymes with high specificity and satisfied activity. Here, a defective copper-cobalt binuclear Prussian blue analogue (CuCoPBA) nanozyme was developed via a facile and ingenious methodology based on single histidine (His)...

Noncatalytic carbohydrate-binding modules (CBMs) play important roles in the function of lytic polysaccharide monooxygenases (LPMOs) but have not been well demonstrated for starch-active AA13 LPMO. In this study, four new CBMs were investigated systematically for their influence on Mt LPMO toward starch in terms of substrate binding, H2 O2 production activity, oxidative product yields, and the degradation effect with α-amylase and glucoamylase toward different starch substrates. Among the four Mt LPMO-CBM chimeras, Mt LPMO- Cn CBM harboring the CBM from Colletotrichum nymphaeae showed the highest substrate binding toward different types of starch compared to Mt LPMO without CBM...

No abstract text is available yet for this article.

BACKGROUND: High substrate concentrations and high sugar yields are important aspects of enzymatic saccharification of lignocellulosic substrates. The benefit of supporting the catalytic action of lytic polysaccharide monooxygenase (LPMO) through continuous aeration of slurries of pretreated softwood was weighed against problems associated with increasing substrate content (quantitated as WIS, water-insoluble solids, in the range 12.5-17.5%), and was compared to the beneficial effect on the saccharification reaction achieved by increasing the enzyme preparation (Cellic CTec3) loadings...

The "Histidine-brace" (His-brace) copper-binding site, composed of Cu(His)2 with a backbone amine, is found in metalloproteins with diverse functions. A primary example is lytic polysaccharide monooxygenase (LPMO), a class of enzymes that catalyze the oxidative depolymerization of polysaccharides, providing not only an energy source for native microorganisms but also a route to more effective industrial biomass conversion. Despite its importance, how the Cu His-brace site performs this unique and challenging oxidative depolymerization reaction remains to be understood...

Lytic polysaccharide monooxygenases (LPMOs) are mono-copper enzymes that use O2 or H2 O2 to oxidatively cleave glycosidic bonds. LPMOs are prevalent in nature, and the functional variation among these enzymes is a topic of great interest. We present the functional characterization of one of the 22 putative AA9-type LPMOs from the fungus Schizophyllum commune, ScLPMO9A. The enzyme, expressed in Escherichia coli, showed C4-oxidative cleavage of amorphous cellulose and soluble cello-oligosaccharides. Activity on xyloglucan, mixed-linkage β-glucan, and glucomannan was also observed, and product profiles differed compared to the well-studied C4-oxidizing NcLPMO9C from Neurospora crassa...

Economic valorization of lignocellulose is paramount to realizing a true circular bioeconomy; however, this requires the development of systems and processes to expand the repertoire of bioproducts beyond current renewable fuels, chemicals, and sustainable materials. Parascedosporium putredinis NO1 is an ascomycete that thrived at the later stages of a wheat-straw composting community culture, indicating a propensity to degrade recalcitrant lignin-enriched biomass, but exists within an underrepresented and underexplored fungal lineage...

Cellobiohydrolases are crucial for cellulose breakdown, but their efficiency on crystalline cellulose is hampered by limited access to single chain ends to initiate hydrolysis. As a result, they depend on enzymes like lytic polysaccharide monooxygenases (LPMOs), which directly target the crystalline cellulose surface. This study investigated how LPMO pretreatment affected the productive binding capacity of a Trichoderma longibrachiatum cellobiohydrolase, TlCBHI, on crystalline cellulose by applying an amperometric cellobiose dehydrogenase biosensor...

The function of cellobiose dehydrogenase (CDH) in biosensors, biofuel cells, and as a physiological redox partner of lytic polysaccharide monooxygenase (LPMO) is based on its role as an electron donor. Before donating electrons to LPMO or electrodes, an interdomain electron transfer from the catalytic FAD-containing dehydrogenase domain to the electron shuttling cytochrome domain of CDH is required. This study investigates the role of two crucial amino acids located at the dehydrogenase domain on domain interaction and interdomain electron transfer by structure-based engineering...

Even though the discovery of lytic polysaccharide monooxygenases (LPMOs) has fundamentally shifted our understanding of biomass degradation, most of the current studies focused on their roles in carbohydrate oxidation. However, no study demonstrated if LPMO could directly participate to the process of lignin degradation in lignin-degrading microbes. This study showed that LPMO could synergize with lignin-degrading enzymes for efficient lignin degradation in white-rot fungi. The transcriptomics analysis of fungi Irpex lacteus and Dichomitus squalens during their lignocellulosic biomass degradation processes surprisingly highlighted that LPMOs co-regulated with lignin-degrading enzymes, indicating their more versatile roles in the redox network...

Lytic polysaccharide monooxygenases (LPMOs) can perform oxidative cleavage of glycosidic bonds in carbohydrate polymers (e.g., cellulose, chitin), making them more accessible to hydrolytic enzymes. While most studies have so far mainly explored the role of LPMOs in a (plant) biomass conversion context, alternative roles and paradigms begin to emerge. The AA10 LPMOs are active on chitin and/or cellulose and mostly found in bacteria and in some viruses and archaea. Interestingly, AA10-encoding genes are also encountered in some pathogenic fungi of the Ustilaginomycetes class, such as Ustilago maydis , responsible for corn smut disease...

Oxygenase and peroxygenase enzymes generate intermediates at their active sites which bring about the controlled functionalization of inert C-H bonds in substrates, such as in the enzymatic conversion of methane to methanol. To be viable catalysts, however, these enzymes must also prevent oxidative damage to essential active site residues, which can occur during both coupled and uncoupled turnover. Herein, we use a combination of stopped-flow spectroscopy, targeted mutagenesis, TD-DFT calculations, high-energy resolution fluorescence detection X-ray absorption spectroscopy, and electron paramagnetic resonance spectroscopy to study two transient intermediates that together form a protective pathway built into the active sites of copper-dependent lytic polysaccharide monooxygenases (LPMOs)...

BACKGROUND: Microbial lytic polysaccharide monooxygenases (LPMOs) cleave diverse biomass polysaccharides, including cellulose and hemicelluloses, by initial oxidation at C1 or C4 of glycan chains. Within the Carbohydrate-Active Enzymes (CAZy) classification, Auxiliary Activity Family 9 (AA9) comprises the first and largest group of fungal LPMOs, which are often also found in tandem with non-catalytic carbohydrate-binding modules (CBMs). LPMOs originally attracted attention for their ability to potentiate complete biomass deconstruction to monosaccharides...

Rice husk is an abundant agricultural waste generated from rice production, but its application is limited. Considering its complex components, the rice husk was hydrolyzed by different enzymes to enhance its saccharification. In this study, saccharification of the rice husk by cellulase, xylosidase, and xylanase was first investigated. The synergistic effect of LPMO on the above hydrolases and different enzyme combinations in the saccharification process was then explored. Thereafter, the formulation of the enzyme cocktail and the degradation conditions were optimized to obtain the highest saccharification efficiency...

Lytic polysaccharide monooxygenases (LPMOs) are powerful redox enzymes that transform complex carbohydrates through oxidation and make them suitable for saccharification by canonical hydrolases. Due to this property, LPMOs are considered to be a valuable component of enzymatic consortia for industrial biorefineries. Tma12 is a fern entomotoxic protein that kills whitefly and has structural similarities with chitinolytic LPMO. However, its enzymatic activity is poorly understood. Studying the role of the LPMO-like activity in the insecticidal function of Tma12 can be of considerable importance...

Lytic polysaccharide monooxygenases (LPMOs) are surface-active redox enzymes that catalyze the degradation of recalcitrant polysaccharides, making them important tools for energy production from renewable sources. In addition, LPMOs are important virulence factors for fungi, bacteria, and viruses. However, many knowledge gaps still exist regarding their catalytic mechanism and interaction with their insoluble, crystalline substrates. Moreover, conventional structural biology techniques, such as X-ray crystallography, usually do not reveal the protonation state of catalytically important residues...

Lytic polysaccharide monooxygenases (LPMOs) are powerful monocopper enzymes that can activate strong C-H bonds through a mechanism that remains largely unknown. Herein, we investigated the role of a conserved glutamine/glutamate in the second coordination sphere. Mutation of the Gln in Nc AA9C to Glu, Asp, or Asn showed that the nature and distance of the headgroup to the copper fine-tune LPMO functionality and copper reactivity. The presence of Glu or Asp close to the copper lowered the reduction potential and decreased the ratio between the reduction and reoxidation rates by up to 500-fold...

Lytic polysaccharide monooxygenases (LPMOs) are monocopper enzymes that degrade the insoluble crystalline polysaccharides cellulose and chitin. Besides the H2 O2 co-substrate, the cleavage of glycosidic bonds by LPMOs depends on the presence of a reductant needed to bring the enzyme into its reduced, catalytically active Cu(I) state. Reduced LPMOs that are not bound to substrate catalyze reductant peroxidase reactions, which may lead to oxidative damage and irreversible inactivation of the enzyme. However, the kinetics of this reaction remain largely unknown, as do possible variations between LPMOs belonging to different families...

Cellulose and chitin are two of the most abundant biopolymers in nature, but they cannot be effectively utilized in industry due to their recalcitrance. This limitation was overcome by the advent of lytic polysaccharide monooxygenases (LPMOs), which promote the disruption of biopolymers through oxidative mechanism and provide a breakthrough in the action of hydrolytic enzymes. In the application of LPMOs to biomass degradation, the key to consistent and effective functioning lies in their stability. The efficient transformation of biomass resources using LPMOs depends on factors that interfere with their stability...