Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Electron transfer in polysaccharide monooxygenase catalysis

Journal Article · · Proceedings of the National Academy of Sciences of the United States of America

Polysaccharide monooxygenase (PMO) catalysis involves the chemically difficult hydroxylation of unactivated C–H bonds in carbohydrates. The reaction requires reducing equivalents and will utilize either oxygen or hydrogen peroxide as a cosubstrate. Two key mechanistic questions are addressed here: 1) How does the enzyme regulate the timely and tightly controlled electron delivery to the mononuclear copper active site, especially when bound substrate occludes the active site? and 2) How does this electron delivery differ when utilizing oxygen or hydrogen peroxide as a cosubstrate? Using a computational approach, potential paths of electron transfer (ET) to the active site copper ion were identified in a representative AA9 family PMO from Myceliophthora thermophila ( Mt PMO9E). When Y62, a buried residue 12 Å from the active site, is mutated to F, lower activity is observed with O 2 . However, a WT-level activity is observed with H 2 O 2 as a cosubstrate indicating an important role in ET for O 2 activation. To better understand the structural effects of mutations to Y62 and axial copper ligand Y168, crystal structures were solved of the wild type Mt PMO9E and the variants Y62W, Y62F, and Y168F. A bioinformatic analysis revealed that position 62 is conserved as either Y or W in the AA9 family. The Mt PMO9E Y62W variant has restored activity with O 2 . Overall, the use of redox-active residues to supply electrons for the reaction with O 2 appears to be widespread in the AA9 family. Furthermore, the results provide a molecular framework to understand catalysis with O 2 versus H 2 O 2 .

Sponsoring Organization:
USDOE
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
2484077
Journal Information:
Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Issue: 1 Vol. 122; ISSN 0027-8424
Publisher:
Proceedings of the National Academy of SciencesCopyright Statement
Country of Publication:
United States
Language:
English

References (48)

Electron Transfer in Peptides with Cysteine and Methionine as Relay Amino Acids journal May 2009
Oxygen Activation at the Active Site of a Fungal Lytic Polysaccharide Monooxygenase journal December 2016
A tale of two methane monooxygenases journal November 2016
Structural perturbations of substrate binding and oxidation state changes in a lytic polysaccharide monooxygenase journal October 2022
The one-electron transfer redox potentials of free radicals. I. The oxygen/superoxide system journal May 1976
Oxidation: An important enzyme reaction in fungal degradation of cellulose journal December 1974
Electrode potentials of partially reduced oxygen species, from dioxygen to water journal August 2010
EFI-EST, EFI-GNT, and EFI-CGFP: Enzyme Function Initiative (EFI) Web Resource for Genomic Enzymology Tools journal July 2023
Recent insights into copper-containing lytic polysaccharide mono-oxygenases journal October 2013
Polysaccharide degradation by lytic polysaccharide monooxygenases journal December 2019
Structural Basis for Substrate Targeting and Catalysis by Fungal Polysaccharide Monooxygenases journal June 2012
Lytic Polysaccharide Monooxygenases in Biomass Conversion journal December 2015
Glycosidic Bond Hydroxylation by Polysaccharide Monooxygenases journal May 2019
A Random-Sequential Kinetic Mechanism for Polysaccharide Monooxygenases journal April 2018
Catalytic Mechanism of Fungal Lytic Polysaccharide Monooxygenases Investigated by First-Principles Calculations journal December 2017
Two Aromatic Rings Coupled a Sulfur-Containing Group to Favor Protein Electron Transfer by Instantaneous Formations of π∴S:π↔π:S∴π or π∴π:S↔π:π∴S Five-Electron Bindings journal April 2015
The Role of the Secondary Coordination Sphere in a Fungal Polysaccharide Monooxygenase journal March 2017
Cellobiose Dehydrogenase and a Copper-Dependent Polysaccharide Monooxygenase Potentiate Cellulose Degradation by Neurospora crassa journal December 2011
Mechanisms Whereby Mononuclear Copper Proteins Functionalize Organic Substrates journal January 1996
Formation of a Copper(II)–Tyrosyl Complex at the Active Site of Lytic Polysaccharide Monooxygenases Following Oxidation by H2O2 journal November 2019
Fast, scalable generation of high‐quality protein multiple sequence alignments using Clustal Omega journal January 2011
Oxidative cleavage of polysaccharides by monocopper enzymes depends on H2O2 journal August 2017
Mutational dissection of a hole hopping route in a lytic polysaccharide monooxygenase (LPMO) journal May 2024
Highly accurate protein structure prediction with AlphaFold journal July 2021
AlphaFill: enriching AlphaFold models with ligands and cofactors journal November 2022
Molecular mechanism of lytic polysaccharide monooxygenases journal January 2018
The role of the active site tyrosine in the mechanism of lytic polysaccharide monooxygenase journal January 2021
On the roles of methionine and the importance of its microenvironments in redox metalloproteins journal January 2022
Functional and protective hole hopping in metalloenzymes journal January 2021
Capture of activated dioxygen intermediates at the copper-active site of a lytic polysaccharide monooxygenase journal January 2022
Revisiting the role of electron donors in lytic polysaccharide monooxygenase biochemistry journal April 2023
Long-range electron transfer journal February 2005
Insights into the oxidative degradation of cellulose by a copper metalloenzyme that exploits biomass components journal August 2011
Interactions of a fungal lytic polysaccharide monooxygenase with β-glucan substrates and cellobiose dehydrogenase journal May 2016
Reactivity of O 2 versus H 2 O 2 with polysaccharide monooxygenases journal April 2018
Mapping hole hopping escape routes in proteins journal July 2019
Kinetic analysis of amino acid radicals formed in H 2 O 2 -driven Cu I LPMO reoxidation implicates dominant homolytic reactivity journal May 2020
Characterization of a unique polysaccharide monooxygenase from the plant pathogen Magnaporthe oryzae journal February 2023
Kinetics of H 2 O 2 -driven degradation of chitin by a bacterial lytic polysaccharide monooxygenase journal November 2017
The Copper-Enzyme Family of Dopamine β-Monooxygenase and Peptidylglycine α-Hydroxylating Monooxygenase: Resolving the Chemical Pathway for Substrate Hydroxylation journal November 2005
Cytoscape: A Software Environment for Integrated Models of Biomolecular Interaction Networks journal November 2003
WebLogo: A Sequence Logo Generator journal May 2004
Changes in active-site geometry on X-ray photoreduction of a lytic polysaccharide monooxygenase active-site copper and saccharide binding journal August 2022
Insights into the H 2 O 2 ‐driven catalytic mechanism of fungal lytic polysaccharide monooxygenases journal January 2021
On the expansion of biological functions of lytic polysaccharide monooxygenases journal January 2022
The crystal structure of human dopamine β-hydroxylase at 2.9 Å resolution journal April 2016
Recovery of particulate methane monooxygenase structure and activity in a lipid bilayer journal March 2022
A moonlighting function of a chitin polysaccharide monooxygenase, CWR-1, in Neurospora crassa allorecognition journal August 2022

Similar Records

Insights into an unusual Auxiliary Activity 9 family member lacking the histidine brace motif of lytic polysaccharide monooxygenases
Journal Article · Thu Aug 29 20:00:00 EDT 2019 · Journal of Biological Chemistry · OSTI ID:1619137

Role for Threonine 201 in the Catalytic Cycle of the Soluble Diiron Hydroxylase Toluene 4-Monooxygenase
Journal Article · Mon Jun 01 00:00:00 EDT 2009 · Biochemistry-US · OSTI ID:1005632

Related Subjects