English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Decoding the Ambiguous Electron Paramagnetic Resonance Signals in the Lytic Polysaccharide Monooxygenase from Photorhabdus luminescens

Gómez-Piñeiro, R. J., Drosou, M., Bertaina, S., Decroos, C., Simaan, A. J., Pantazis, D. A., et al. (2022). Decoding the Ambiguous Electron Paramagnetic Resonance Signals in the Lytic Polysaccharide Monooxygenase from Photorhabdus luminescens. Inorganic Chemistry, 61(20), 8022-8035. doi:10.1021/acs.inorgchem.2c00766.

Item is

Files

show Files

Locators

show

Creators

show
hide
 Creators:
Gómez-Piñeiro, Rogelio J.1, Author
Drosou, Maria2, Author
Bertaina, Sylvain3, Author
Decroos, Christophe1, Author
Simaan, A. Jalila1, Author
Pantazis, Dimitrios A.4, Author           
Orio, Maylis1, Author
Affiliations:
1Aix Marseille Université, CNRS, Centrale Marseille, iSm2, Marseille 13397, France, ou_persistent22              
2Inorganic Chemistry Laboratory, National and Kapodistrian University of Athens, Panepistimiopolis, Zografou 15771, Greece, ou_persistent22              
3Aix-Marseille Université, CNRS, IM2NP UMR 7334, Marseille 13397, France, ou_persistent22              
4Research Group Pantazis, Max-Planck-Institut für Kohlenforschung, Max Planck Society, ou_2541711              

Content

show
hide
Free keywords: -
 Abstract: Understanding the structure and function of lytic polysaccharide monooxygenases (LPMOs), copper enzymes that degrade recalcitrant polysaccharides, requires the reliable atomistic interpretation of electron paramagnetic resonance (EPR) data on the Cu(II) active site. Among various LPMO families, the chitin-active PlAA10 shows an intriguing phenomenology with distinct EPR signals, a major rhombic and a minor axial signal. Here, we combine experimental and computational investigations to uncover the structural identity of these signals. X-band EPR spectra recorded at different pH values demonstrate pH-dependent population inversion: the major rhombic signal at pH 6.5 becomes minor at pH 8.5, where the axial signal dominates. This suggests that a protonation change is involved in the interconversion. Precise structural interpretations are pursued with quantum chemical calculations. Given that accurate calculations of Cu g-tensors remain challenging for quantum chemistry, we first address this problem via a thorough calibration study. This enables us to define a density functional that achieves accurate and reliable prediction of g-tensors, giving confidence in our evaluation of PlAA10 LPMO models. Large models were considered that include all parts of the protein matrix surrounding the Cu site, along with the characteristic second-sphere features of PlAA10. The results uniquely identify the rhombic signal with a five-coordinate Cu ion bearing two water molecules in addition to three N-donor ligands. The axial signal is attributed to a four-coordinate Cu ion where only one of the waters remains bound, as hydroxy. Alternatives that involve decoordination of the histidine brace amino group are unlikely based on energetics and spectroscopy. These results provide a reliable spectroscopy-consistent view on the plasticity of the resting state in PlAA10 LPMO as a foundation for further elucidating structure–property relationships and the formation of catalytically competent species. Our strategy is generally applicable to the study of EPR parameters of mononuclear copper-containing metalloenzymes.

Details

show
hide
Language(s): eng - English
 Dates: 2022-03-082022-05-122022-05-23
 Publication Status: Issued
 Pages: 14
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1021/acs.inorgchem.2c00766
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Inorganic Chemistry
  Abbreviation : Inorg. Chem.
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: Washington, DC : American Chemical Society
Pages: - Volume / Issue: 61 (20) Sequence Number: - Start / End Page: 8022 - 8035 Identifier: ISSN: 0020-1669
CoNE: https://pure.mpg.de/cone/journals/resource/0020-1669