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McGraw M, Addison B, Clarke RW, Allen RD, Rorrer NA. Synergistic Dual-Cure Reactions for the Fabrication of Thermosets by Chemical Heating. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2024; 12:11913-11927. [PMID: 39148515 PMCID: PMC11323266 DOI: 10.1021/acssuschemeng.4c01965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 07/24/2024] [Accepted: 07/24/2024] [Indexed: 08/17/2024]
Abstract
Large composite structures, such as those used in wind energy applications, rely on the bulk polymerization of thermosets on an impressively large scale. To accomplish this, traditional thermoset polymerizations require both elevated temperatures (>100 °C) and extended cure durations (>5 h) for complete conversion, necessitating the use of oversize ovens or heated molds. In turn, these requirements lead to energy-intensive polymerizations, incurring high manufacturing costs and process emissions. In this study, we develop thermoset polymerizations that can be initiated at room temperature through a transformative "chemical heating" concept, in which the exothermic energy of a secondary reaction is used to facilitate the heating of a primary thermoset polymerization. By leveraging a redox-initiated methacrylate free radical polymerization as a source of exothermic chemical energy, we can achieve peak reaction temperatures >140 °C to initiate the polymerization of epoxy-anhydride thermosets without external heating. Furthermore, by employing Trojan horse methacrylate monomers to induce mixing between methacrylate and epoxy-anhydride domains, we achieve the synthesis of homogeneous hybrid polymeric materials with competitive thermomechanical properties and tunability. Herein, we establish a proof-of-concept for our innovative chemical heating method and advocate for its industrial integration for more energy-efficient and streamlined manufacturing of wind blades and large composite parts more broadly.
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Affiliation(s)
- Michael
L. McGraw
- Renewable Resources and Enabling
Sciences Center, National Renewable Energy
Laboratory, Golden, Colorado 80401, United States
| | - Bennett Addison
- Renewable Resources and Enabling
Sciences Center, National Renewable Energy
Laboratory, Golden, Colorado 80401, United States
| | - Ryan W. Clarke
- Renewable Resources and Enabling
Sciences Center, National Renewable Energy
Laboratory, Golden, Colorado 80401, United States
| | - Robert D. Allen
- Renewable Resources and Enabling
Sciences Center, National Renewable Energy
Laboratory, Golden, Colorado 80401, United States
| | - Nicholas A. Rorrer
- Renewable Resources and Enabling
Sciences Center, National Renewable Energy
Laboratory, Golden, Colorado 80401, United States
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2
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Chalek K, Soni A, Lorenz CD, Holland GP. Proline-Tyrosine Ring Interactions in Black Widow Dragline Silk Revealed by Solid-State Nuclear Magnetic Resonance and Molecular Dynamics Simulations. Biomacromolecules 2024; 25:1916-1922. [PMID: 38315982 DOI: 10.1021/acs.biomac.3c01351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Selective one-dimensional 13C-13C spin-diffusion solid-state nuclear magnetic resonance (SSNMR) provides evidence for CH/π ring packing interactions between Pro and Tyr residues in 13C-enriched Latrodectus hesperus dragline silk. The secondary structure of Pro-containing motifs in dragline spider silks consistently points to an elastin-like type II β-turn conformation based on 13C chemical shift analysis. 13C-13C spin diffusion measurements as a function of mixing times allow for the measurement of spatial proximity between the Pro and Tyr rings to be ∼0.5-1 nm, supporting strong Pro-Tyr ring interactions that likely occur through a CH/π mechanism. These results are supported by molecular dynamics (MD) simulations and analysis and reveals new insights into the secondary structure and Pro-Tyr ring stacking interactions for one of nature's toughest biomaterials.
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Affiliation(s)
- Kevin Chalek
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92181-1030, United States
| | - Ashana Soni
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92181-1030, United States
| | - Christian D Lorenz
- Biological Physics & Soft Matter Group, Department of Physics, King's College London, London WC2R 2LS, United Kingdom
| | - Gregory P Holland
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92181-1030, United States
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3
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Kim Y, Alia A, Kurle-Tucholski P, Wiebeler C, Matysik J. Electronic Structures of Radical-Pair-Forming Cofactors in a Heliobacterial Reaction Center. Molecules 2024; 29:1021. [PMID: 38474533 DOI: 10.3390/molecules29051021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/16/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024] Open
Abstract
Photosynthetic reaction centers (RCs) are membrane proteins converting photonic excitations into electric gradients. The heliobacterial RCs (HbRCs) are assumed to be the precursors of all known RCs, making them a compelling subject for investigating structural and functional relationships. A comprehensive picture of the electronic structure of the HbRCs is still missing. In this work, the combination of selective isotope labelling of 13C and 15N nuclei and the utilization of photo-CIDNP MAS NMR (photochemically induced dynamic nuclear polarization magic-angle spinning nuclear magnetic resonance) allows for highly enhanced signals from the radical-pair-forming cofactors. The remarkable magnetic-field dependence of the solid-state photo-CIDNP effect allows for observation of positive signals of the electron donor cofactor at 4.7 T, which is interpreted in terms of a dominant contribution of the differential relaxation (DR) mechanism. Conversely, at 9.4 T, the emissive signals mainly originate from the electron acceptor, due to the strong activation of the three-spin mixing (TSM) mechanism. Consequently, we have utilized two-dimensional homonuclear photo-CIDNP MAS NMR at both 4.7 T and 9.4 T. These findings from experimental investigations are corroborated by calculations based on density functional theory (DFT). This allows us to present a comprehensive investigation of the electronic structure of the cofactors involved in electron transfer (ET).
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Affiliation(s)
- Yunmi Kim
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
| | - A Alia
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2301 RA Leiden, The Netherlands
- Institut für Medizinische Physik und Biophysik, Universität Leipzig, Härtelstr. 16-18, D-04107 Leipzig, Germany
| | - Patrick Kurle-Tucholski
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
| | - Christian Wiebeler
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
- Institut für Physik, Universität Augsburg, Universitätsstraße 1, D-86159 Augsburg, Germany
| | - Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
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4
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Addison B, Bu L, Bharadwaj V, Crowley MF, Harman-Ware AE, Crowley MF, Bomble YJ, Ciesielski PN. Atomistic, macromolecular model of the Populus secondary cell wall informed by solid-state NMR. SCIENCE ADVANCES 2024; 10:eadi7965. [PMID: 38170770 PMCID: PMC10776008 DOI: 10.1126/sciadv.adi7965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 12/01/2023] [Indexed: 01/05/2024]
Abstract
Plant secondary cell walls (SCWs) are composed of a heterogeneous interplay of three major biopolymers: cellulose, hemicelluloses, and lignin. Details regarding specific intermolecular interactions and higher-order architecture of the SCW superstructure remain ambiguous. Here, we use solid-state nuclear magnetic resonance (ssNMR) measurements to infer refined details about the structural configuration, intermolecular interactions, and relative proximity of all three major biopolymers within air-dried Populus wood. To enhance the utility of these findings and enable evaluation of hypotheses in a physics-based environment in silico, the NMR observables are articulated into an atomistic, macromolecular model for biopolymer assemblies within the plant SCW. Through molecular dynamics simulation, we quantitatively evaluate several variations of atomistic models to determine structural details that are corroborated by ssNMR measurements.
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Affiliation(s)
- Bennett Addison
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Lintao Bu
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Vivek Bharadwaj
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Meagan F. Crowley
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
- Chemistry Department, Colorado School of Mines, Golden, CO, USA
| | - Anne E. Harman-Ware
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Michael F. Crowley
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Yannick J. Bomble
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Peter N. Ciesielski
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
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5
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Fernando LD, Zhao W, Gautam I, Ankur A, Wang T. Polysaccharide assemblies in fungal and plant cell walls explored by solid-state NMR. Structure 2023; 31:1375-1385. [PMID: 37597511 PMCID: PMC10843855 DOI: 10.1016/j.str.2023.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/30/2023] [Accepted: 07/26/2023] [Indexed: 08/21/2023]
Abstract
Structural analysis of macromolecular complexes within their natural cellular environment presents a significant challenge. Recent applications of solid-state NMR (ssNMR) techniques on living fungal cells and intact plant tissues have greatly enhanced our understanding of the structure of extracellular matrices. Here, we selectively highlight the most recent progress in this field. Specifically, we discuss how ssNMR can provide detailed insights into the chemical composition and conformational structure of pectin, and the consequential impact on polysaccharide interactions and cell wall organization. We elaborate on the use of ssNMR data to uncover the arrangement of the lignin-polysaccharide interface and the macrofibrillar structure in native plant stems or during degradation processes. We also comprehend the dynamic structure of fungal cell walls under various morphotypes and stress conditions. Finally, we assess how the combination of NMR with other techniques can enhance our capacity to address unresolved structural questions concerning these complex macromolecular assemblies.
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Affiliation(s)
- Liyanage D Fernando
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Wancheng Zhao
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Isha Gautam
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Ankur Ankur
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Tuo Wang
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA.
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6
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Derba-Maceluch M, Mitra M, Hedenström M, Liu X, Gandla ML, Barbut FR, Abreu IN, Donev EN, Urbancsok J, Moritz T, Jönsson LJ, Tsang A, Powlowski J, Master ER, Mellerowicz EJ. Xylan glucuronic acid side chains fix suberin-like aliphatic compounds to wood cell walls. THE NEW PHYTOLOGIST 2023; 238:297-312. [PMID: 36600379 DOI: 10.1111/nph.18712] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Wood is the most important repository of assimilated carbon in the biosphere, in the form of large polymers (cellulose, hemicelluloses including glucuronoxylan, and lignin) that interactively form a composite, together with soluble extractives including phenolic and aliphatic compounds. Molecular interactions among these compounds are not fully understood. We have targeted the expression of a fungal α-glucuronidase to the wood cell wall of aspen (Populus tremula L. × tremuloides Michx.) and Arabidopsis (Arabidopsis thaliana (L.) Heynh), to decrease contents of the 4-O-methyl glucuronopyranose acid (mGlcA) substituent of xylan, to elucidate mGlcA's functions. The enzyme affected the content of aliphatic insoluble cell wall components having composition similar to suberin, which required mGlcA for binding to cell walls. Such suberin-like compounds have been previously identified in decayed wood, but here, we show their presence in healthy wood of both hardwood and softwood species. By contrast, γ-ester bonds between mGlcA and lignin were insensitive to cell wall-localized α-glucuronidase, supporting the intracellular formation of these bonds. These findings challenge the current view of the wood cell wall composition and reveal a novel function of mGlcA substituent of xylan in fastening of suberin-like compounds to cell wall. They also suggest an intracellular initiation of lignin-carbohydrate complex assembly.
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Affiliation(s)
- Marta Derba-Maceluch
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - Madhusree Mitra
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | | | - Xiaokun Liu
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | | | - Félix R Barbut
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - Ilka N Abreu
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - Evgeniy N Donev
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - János Urbancsok
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - Thomas Moritz
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - Leif J Jönsson
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, Montreal, QC, H4B 1R6, Canada
| | - Justin Powlowski
- Centre for Structural and Functional Genomics, Concordia University, Montreal, QC, H4B 1R6, Canada
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Ewa J Mellerowicz
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
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7
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Stengel D, Saric M, Johnson HR, Schiller T, Diehl J, Chalek K, Onofrei D, Scheibel T, Holland GP. Tyrosine's Unique Role in the Hierarchical Assembly of Recombinant Spider Silk Proteins: From Spinning Dope to Fibers. Biomacromolecules 2023; 24:1463-1474. [PMID: 36791420 DOI: 10.1021/acs.biomac.2c01467] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Producing recombinant spider silk fibers that exhibit mechanical properties approaching native spider silk is highly dependent on the constitution of the spinning dope. Previously published work has shown that recombinant spider silk fibers spun from dopes with phosphate-induced pre-assembly (biomimetic dopes) display a toughness approaching native spider silks far exceeding the mechanical properties of fibers spun from dopes without pre-assembly (classical dopes). Dynamic light scattering experiments comparing the two dopes reveal that biomimetic dope displays a systematic increase in assembly size over time, while light microscopy indicates liquid-liquid-phase separation (LLPS) as evidenced by the formation of micron-scale liquid droplets. Solution nuclear magnetic resonance (NMR) shows that the structural state in classical and biomimetic dopes displays a general random coil conformation in both cases; however, some subtle but distinct differences are observed, including a more ordered state for the biomimetic dope and small chemical shift perturbations indicating differences in hydrogen bonding of the protein in the different dopes with notable changes occurring for Tyr residues. Solid-state NMR demonstrates that the final wet-spun fibers from the two dopes display no structural differences of the poly(Ala) stretches, but biomimetic fibers display a significant difference in Tyr ring packing in non-β-sheet, disordered helical domains that can be traced back to differences in dope preparations. It is concluded that phosphate pre-orders the recombinant silk protein in biomimetic dopes resulting in LLPS and fibers that exhibit vastly improved toughness that could be due to aromatic ring packing differences in non-β-sheet domains that contain Tyr.
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Affiliation(s)
- Dillan Stengel
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Dr, San Diego, California 92182-1030, United States
| | - Merisa Saric
- Lehrstuhl Biomaterialien, Fakultät für Ingenieurwissenschaften, Universität Bayreuth, Prof.-Rüdiger-Bormann-Street 1, Bayreuth 95447, Germany
| | - Hannah R Johnson
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Dr, San Diego, California 92182-1030, United States
| | - Tim Schiller
- Lehrstuhl Biomaterialien, Fakultät für Ingenieurwissenschaften, Universität Bayreuth, Prof.-Rüdiger-Bormann-Street 1, Bayreuth 95447, Germany
| | - Johannes Diehl
- Lehrstuhl Biomaterialien, Fakultät für Ingenieurwissenschaften, Universität Bayreuth, Prof.-Rüdiger-Bormann-Street 1, Bayreuth 95447, Germany
| | - Kevin Chalek
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Dr, San Diego, California 92182-1030, United States
| | - David Onofrei
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Dr, San Diego, California 92182-1030, United States
| | - Thomas Scheibel
- Lehrstuhl Biomaterialien, Fakultät für Ingenieurwissenschaften, Universität Bayreuth, Prof.-Rüdiger-Bormann-Street 1, Bayreuth 95447, Germany
| | - Gregory P Holland
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Dr, San Diego, California 92182-1030, United States
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Munson CR, Gao Y, Mortimer JC, Murray DT. Solid-State Nuclear Magnetic Resonance as a Tool to Probe the Impact of Mechanical Preprocessing on the Structure and Arrangement of Plant Cell Wall Polymers. FRONTIERS IN PLANT SCIENCE 2022; 12:766506. [PMID: 35095947 PMCID: PMC8790750 DOI: 10.3389/fpls.2021.766506] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 11/25/2021] [Indexed: 06/14/2023]
Abstract
Efficient separation of the plant cell wall polymers during lignocellulose processing has been historically challenging due to insolubility of the polymers and their propensity for recalcitrant reassembly. Methods, such as "lignin first" extraction techniques, have advanced efficient biomass use, but the molecular mechanisms for recalcitrance remain enigmatic. Here, we discuss how solid-state Nuclear Magnetic Resonance (NMR) approaches report on the 3D organization of cellulose, xylan, and lignin in the plant cell wall. Recent results illustrate that the organization of these polymers varies across biomass sources and sample preparation methods, with even minimal physical processing causing significant effects. These structural differences contribute to variable extraction efficiencies for bioproducts after downstream processing. We propose that solid-state NMR methods can be applied to follow biomass processing, providing an understanding of the polymer rearrangements that can lead to poor yields for the desired bioproducts. The utility of the technique is illustrated for mechanical processing using lab-scale vibratory ball milling of Sorghum bicolor.
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Affiliation(s)
- Coyla R. Munson
- Department of Chemistry, University of California, Davis, Davis, CA, United States
| | - Yu Gao
- Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Jenny C. Mortimer
- Joint BioEnergy Institute, Emeryville, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, SA, Australia
| | - Dylan T. Murray
- Department of Chemistry, University of California, Davis, Davis, CA, United States
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9
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Ghassemi N, Poulhazan A, Deligey F, Mentink-Vigier F, Marcotte I, Wang T. Solid-State NMR Investigations of Extracellular Matrixes and Cell Walls of Algae, Bacteria, Fungi, and Plants. Chem Rev 2021; 122:10036-10086. [PMID: 34878762 DOI: 10.1021/acs.chemrev.1c00669] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Extracellular matrixes (ECMs), such as the cell walls and biofilms, are important for supporting cell integrity and function and regulating intercellular communication. These biomaterials are also of significant interest to the production of biofuels and the development of antimicrobial treatment. Solid-state nuclear magnetic resonance (ssNMR) and magic-angle spinning-dynamic nuclear polarization (MAS-DNP) are uniquely powerful for understanding the conformational structure, dynamical characteristics, and supramolecular assemblies of carbohydrates and other biomolecules in ECMs. This review highlights the recent high-resolution investigations of intact ECMs and native cells in many organisms spanning across plants, bacteria, fungi, and algae. We spotlight the structural principles identified in ECMs, discuss the current technical limitation and underexplored biochemical topics, and point out the promising opportunities enabled by the recent advances of the rapidly evolving ssNMR technology.
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Affiliation(s)
- Nader Ghassemi
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Alexandre Poulhazan
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.,Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Fabien Deligey
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | | | - Isabelle Marcotte
- Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Tuo Wang
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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10
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Lyczakowski JJ, Yu L, Terrett OM, Fleischmann C, Temple H, Thorlby G, Sorieul M, Dupree P. Two conifer GUX clades are responsible for distinct glucuronic acid patterns on xylan. THE NEW PHYTOLOGIST 2021; 231:1720-1733. [PMID: 34086997 DOI: 10.1111/nph.17531] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/21/2021] [Indexed: 06/12/2023]
Abstract
Wood of coniferous trees (softwood), is a globally significant carbon sink and an important source of biomass. Despite that, little is known about the genetic basis of softwood cell wall biosynthesis. Branching of xylan, one of the main hemicelluloses in softwood secondary cell walls, with glucuronic acid (GlcA) is critical for biomass recalcitrance. Here, we investigate the decoration patterns of xylan by conifer GlucUronic acid substitution of Xylan (GUX) enzymes. Through molecular phylogenetics we identify two distinct conifer GUX clades. Using transcriptional profiling we show that the genes are preferentially expressed in secondary cell wall forming tissues. With in vitro and in planta assays we demonstrate that conifer GUX enzymes from both clades are active glucuronyltransferases. Conifer GUX enzymes from each clade have different specific activities. While members of clade one add evenly spaced GlcA branches, the members of clade two are also capable of glucuronidating two consecutive xyloses. Importantly, these types of xylan patterning are present in softwood. As xylan patterning might modulate xylan-cellulose and xylan-lignin interactions, our results further the understanding of softwood cell wall biosynthesis and provide breeding or genetic engineering targets that can be used to modify softwood properties.
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Affiliation(s)
- Jan J Lyczakowski
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow, 30-387, Poland
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Li Yu
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Oliver M Terrett
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | | | - Henry Temple
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | | | | | - Paul Dupree
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
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11
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Sun SC, Sun D, Cao XF. Effect of integrated treatment on enhancing the enzymatic hydrolysis of cocksfoot grass and the structural characteristics of co-produced hemicelluloses. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:88. [PMID: 33827662 PMCID: PMC8028065 DOI: 10.1186/s13068-021-01944-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Cocksfoot grass (Dactylis glomerata L.) with high biomass yield and rich cellulose can be used to produce bioethanol as fuel additive. In view of this, ultrasonic and hydrothermal pretreatments followed by successive alkali extractions were assembled into an integrated biorefinery process applied on cocksfoot grass to improve its enzymatic hydrolysis. In this work, the effects of ultrasonic and hydrothermal pretreatments followed by sequential alkali extractions on the enzymatic hydrolysis of cocksfoot grass were investigated. In addition, since large amount of hemicelluloses were released during the hydrothermal pretreatment and alkali extraction process, the yields, structural characteristics and differentials of water- and alkali-soluble hemicellulosic fractions isolated from different treatments were also comparatively explored. RESULTS The integrated treatment significantly removed amorphous hemicelluloses and lignin, resulting in increased crystallinity of the treated residues. A maximum saccharification rate of 95.1% was obtained from the cellulose-rich substrate after the integrated treatment. In addition, the considerable hemicelluloses (31.4% water-soluble hemicelluloses and 53.4% alkali-soluble hemicelluloses) were isolated during the integrated treatment. The released water-soluble hemicellulosic fractions were found to be more branched as compared with the alkali-soluble hemicellulosic fractions and all hemicellulosic fractions were mixed polysaccharides mainly composed of branched xylans and β-glucans. CONCLUSION The combination of ultrasonic and hydrothermal pretreatments followed by successive alkali extractions can dramatically increase the enzymatic saccharification rate of the substrates and produce considerable amounts of hemicelluloses. Detailed information about the enzymatic hydrolysis rates of the treated substrates and the structural characteristics of the co-produced hemicelluloses will help the synergistic utilization of cellulose and hemicellulose in cocksfoot grass.
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Affiliation(s)
- Shao-Chao Sun
- Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
| | - Dan Sun
- Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
| | - Xue-Fei Cao
- Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083 China
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