scholarly journals Inside Cover: Oxygen Activation at the Active Site of a Fungal Lytic Polysaccharide Monooxygenase (Angew. Chem. Int. Ed. 3/2017)

2016 ◽  
Vol 56 (3) ◽  
pp. 658-658
Author(s):  
William B. O'Dell ◽  
Pratul K. Agarwal ◽  
Flora Meilleur
Keyword(s):  
Active Site ◽  
Oxygen Activation ◽  
Lytic Polysaccharide Monooxygenase ◽  
Polysaccharide Monooxygenase

scholarly journals Oxygen Activation at the Active Site of a Fungal Lytic Polysaccharide Monooxygenase

2016 ◽  
Vol 129 (3) ◽  
pp. 785-788 ◽  
Author(s):  
William B. O'Dell ◽  
Pratul K. Agarwal ◽  
Flora Meilleur
Keyword(s):  
Active Site ◽  
Oxygen Activation ◽  
Lytic Polysaccharide Monooxygenase ◽  
Polysaccharide Monooxygenase

scholarly journals The role of the active site tyrosine in the mechanism of lytic polysaccharide monooxygenase

2021 ◽  
Vol 12 (1) ◽  
pp. 352-362
Author(s):  
Aina McEvoy ◽  
Joel Creutzberg ◽  
Raushan K. Singh ◽  
Morten J. Bjerrum ◽  
Erik D. Hedegård
Keyword(s):  
Active Site ◽  
Lytic Polysaccharide Monooxygenase ◽  
Lytic Polysaccharide Monooxygenases ◽  
Polysaccharide Monooxygenases ◽  
Active Site Tyrosine ◽  
Polysaccharide Monooxygenase

With QM/MM, we investigate the mechanism of tyrosine deprotonation in lytic polysaccharide monooxygenases. Our results support deprotonation and our calculated UV-vis spectra show that two isomers must be formed to match recent experiments.

scholarly journals Mapping the protonation states of the histidine brace in an AA10 lytic polysaccharide monooxygenase using CW-EPR spectroscopy and DFT calculations

2021 ◽  
Author(s):  
Peter J Lindley ◽  
Alison Parkin ◽  
Gideon Davies ◽  
Paul Howard Walton
Keyword(s):  
Dft Calculations ◽  
Epr Spectroscopy ◽  
Active Site ◽  
Copper Ion ◽  
Lytic Polysaccharide Monooxygenase ◽  
Polysaccharide Monooxygenase

The active site of the polysaccharide-degrading lytic polysaccharide monooxygenase (LPMO) enzymes features a single copper ion coordinated by a histidine brace. The primary coordnation sphere of the copper contains several...

scholarly journals A Lytic Polysaccharide Monooxygenase with Broad Xyloglucan Specificity from the Brown-Rot Fungus Gloeophyllum trabeum and Its Action on Cellulose-Xyloglucan Complexes

2016 ◽  
Vol 82 (22) ◽  
pp. 6557-6572 ◽  
Author(s):  
Yuka Kojima ◽  
Anikó Várnai ◽  
Takuya Ishida ◽  
Naoki Sunagawa ◽  
Dejan M. Petrovic ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Dynamic Viscosity ◽  
Brown Rot ◽  
Primary Cell Wall ◽  
Gloeophyllum Trabeum ◽  
Lytic Polysaccharide Monooxygenase ◽  
Content Type ◽  
Brown Rot Fungus ◽  
Sensitive Method ◽  
Polysaccharide Monooxygenase

ABSTRACTFungi secrete a set of glycoside hydrolases and lytic polysaccharide monooxygenases (LPMOs) to degrade plant polysaccharides. Brown-rot fungi, such asGloeophyllum trabeum, tend to have few LPMOs, and information on these enzymes is scarce. The genome ofG. trabeumencodes four auxiliary activity 9 (AA9) LPMOs (GtLPMO9s), whose coding sequences were amplified from cDNA. Due to alternative splicing, two variants ofGtLPMO9A seem to be produced, a single-domain variant,GtLPMO9A-1, and a longer variant,GtLPMO9A-2, which contains a C-terminal domain comprising approximately 55 residues without a predicted function. We have overexpressed the phylogenetically distinctGtLPMO9A-2 inPichia pastorisand investigated its properties. Standard analyses using high-performance anion-exchange chromatography–pulsed amperometric detection (HPAEC-PAD) and mass spectrometry (MS) showed thatGtLPMO9A-2 is active on cellulose, carboxymethyl cellulose, and xyloglucan. Importantly, compared to other known xyloglucan-active LPMOs,GtLPMO9A-2 has broad specificity, cleaving at any position along the β-glucan backbone of xyloglucan, regardless of substitutions. Using dynamic viscosity measurements to compare the hemicellulolytic action ofGtLPMO9A-2 to that of a well-characterized hemicellulolytic LPMO,NcLPMO9C fromNeurospora crassarevealed thatGtLPMO9A-2 is more efficient in depolymerizing xyloglucan. These measurements also revealed minor activity on glucomannan that could not be detected by the analysis of soluble products by HPAEC-PAD and MS and that was lower than the activity ofNcLPMO9C. Experiments with copolymeric substrates showed an inhibitory effect of hemicellulose coating on cellulolytic LPMO activity and did not reveal additional activities ofGtLPMO9A-2. These results provide insight into the LPMO potential ofG. trabeumand provide a novel sensitive method, a measurement of dynamic viscosity, for monitoring LPMO activity.IMPORTANCECurrently, there are only a few methods available to analyze end products of lytic polysaccharide monooxygenase (LPMO) activity, the most common ones being liquid chromatography and mass spectrometry. Here, we present an alternative and sensitive method based on measurement of dynamic viscosity for real-time continuous monitoring of LPMO activity in the presence of water-soluble hemicelluloses, such as xyloglucan. We have used both these novel and existing analytical methods to characterize a xyloglucan-active LPMO from a brown-rot fungus. This enzyme,GtLPMO9A-2, differs from previously characterized LPMOs in having broad substrate specificity, enabling almost random cleavage of the xyloglucan backbone.GtLPMO9A-2 acts preferentially on free xyloglucan, suggesting a preference for xyloglucan chains that tether cellulose fibers together. The xyloglucan-degrading potential ofGtLPMO9A-2 suggests a role in decreasing wood strength at the initial stage of brown rot through degradation of the primary cell wall.

scholarly journals Direct coordination of pterin to FeII enables neurotransmitter biosynthesis in the pterin-dependent hydroxylases

2021 ◽  
Vol 118 (15) ◽  
pp. e2022379118
Author(s):  
Shyam R. Iyer ◽  
Kasper D. Tidemand ◽  
Jeffrey T. Babicz ◽  
Ariel B. Jacobs ◽  
Leland B. Gee ◽  
...  
Keyword(s):  
Active Site ◽  
Tryptophan Hydroxylase ◽  
Activation Barrier ◽  
Magnetic Circular Dichroism ◽  
Aromatic Amino Acids ◽  
Oxygen Activation ◽  
Nonheme Iron ◽  
Nonheme Iron Enzymes ◽  
Iron Enzymes ◽  
Pterin Cofactor

The pterin-dependent nonheme iron enzymes hydroxylate aromatic amino acids to perform the biosynthesis of neurotransmitters to maintain proper brain function. These enzymes activate oxygen using a pterin cofactor and an aromatic amino acid substrate bound to the FeII active site to form a highly reactive FeIV = O species that initiates substrate oxidation. In this study, using tryptophan hydroxylase, we have kinetically generated a pre-FeIV = O intermediate and characterized its structure as a FeII-peroxy-pterin species using absorption, Mössbauer, resonance Raman, and nuclear resonance vibrational spectroscopies. From parallel characterization of the pterin cofactor and tryptophan substrate–bound ternary FeII active site before the O2 reaction (including magnetic circular dichroism spectroscopy), these studies both experimentally define the mechanism of FeIV = O formation and demonstrate that the carbonyl functional group on the pterin is directly coordinated to the FeII site in both the ternary complex and the peroxo intermediate. Reaction coordinate calculations predict a 14 kcal/mol reduction in the oxygen activation barrier due to the direct binding of the pterin carbonyl to the FeII site, as this interaction provides an orbital pathway for efficient electron transfer from the pterin cofactor to the iron center. This direct coordination of the pterin cofactor enables the biological function of the pterin-dependent hydroxylases and demonstrates a unified mechanism for oxygen activation by the cofactor-dependent nonheme iron enzymes.

scholarly journals Recent Advances in Screening Methods for the Functional Investigation of Lytic Polysaccharide Monooxygenases

2021 ◽  
Vol 9 ◽  
Author(s):  
Damao Wang ◽  
Yanping Li ◽  
Yuting Zheng ◽  
Yves S. Y. Hsieh
Keyword(s):  
Copper Ions ◽  
Biomass Conversion ◽  
Screening Methods ◽  
Lytic Polysaccharide Monooxygenase ◽  
Indirect Measurements ◽  
Glycosidic Bonds ◽  
Lytic Polysaccharide Monooxygenases ◽  
Polysaccharide Monooxygenases ◽  
Functional Investigation ◽  
Polysaccharide Monooxygenase

Lytic polysaccharide monooxygenase (LPMO) is a newly discovered and widely studied enzyme in recent years. These enzymes play a key role in the depolymerization of sugar-based biopolymers (including cellulose, hemicellulose, chitin and starch), and have a positive significance for biomass conversion. LPMO is a copper-dependent enzyme that can oxidize and cleave glycosidic bonds in cellulose and other polysaccharides. Their mechanism of action depends on the correct coordination of copper ions in the active site. There are still difficulties in the analysis of LPMO activity, which often requires multiple methods to be used in concert. In this review, we discussed various LPMO activity analysis methods reported so far, including mature mass spectrometry, chromatography, labeling, and indirect measurements, and summarized the advantages, disadvantages and applicability of different methods.

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