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Chen H, Jiang B, Zou C, Lou Z, Song J, Wu W, Jin Y. Exploring how lignin structure influences the interaction between carbohydrate-binding module and lignin using AFM. Int J Biol Macromol 2023; 232:123313. [PMID: 36682668 DOI: 10.1016/j.ijbiomac.2023.123313] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/23/2022] [Accepted: 01/13/2023] [Indexed: 01/22/2023]
Abstract
Nonproductive adsorption of cellulase onto the residual lignin in substrate seriously hinders the enzymatic hydrolysis. To understand how lignin structure affects lignin-cellulase interaction, the carbohydrate-binding module (CBM) functionalized atomic force microscope tip was used to measure CBM-lignin interaction by single-molecule dynamic force spectroscopy in this work. The results showed that sulfonated lignin (SL) has the greatest adhesion force to CBM (4.74 nN), while those of masson pine milled wood lignin (MWL), poplar MWL and herbaceous MWLs were 2.85, 1.03 and 0.27-0.61 nN, respectively. It provides direct quantitative evidence for the significance of lignin structure on lignin-cellulase interaction. The CBM-MWLs interaction decreased sharply to 0.054-0.083 nN while SL was added, indicating the primary mechanism of SL promoting lignocellulose hydrolysis was significantly reducing the nonproductive adsorption of substrate lignin on cellulase. Finally, the "competitive adsorption" mechanism was proposed to interpret why SL effectively promotes the enzymatic hydrolysis of lignin-containing substrates.
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Affiliation(s)
- Hui Chen
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China; Joint International Research Lab of Lignocellulosic Functional Materials, International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China
| | - Bo Jiang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China; Joint International Research Lab of Lignocellulosic Functional Materials, International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China
| | - Chunyang Zou
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Zhichao Lou
- Joint International Research Lab of Lignocellulosic Functional Materials, International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China
| | - Junlong Song
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China; Joint International Research Lab of Lignocellulosic Functional Materials, International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China
| | - Wenjuan Wu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China.
| | - Yongcan Jin
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China; Joint International Research Lab of Lignocellulosic Functional Materials, International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China.
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2
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Li L, Ji J, Song F, Hu J. Intercellular Receptor-ligand Binding: Effect of Protein-membrane Interaction. J Mol Biol 2023; 435:167787. [PMID: 35952805 DOI: 10.1016/j.jmb.2022.167787] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/03/2022] [Accepted: 08/04/2022] [Indexed: 02/04/2023]
Abstract
Gaining insights into the intercellular receptor-ligand binding is of great importance for understanding numerous physiological and pathological processes, and stimulating new strategies in drug design and discovery. In contrast to the in vitro protein interaction in solution, the anchored receptor and ligand molecules interact with membrane in situ, which affects the intercellular receptor-ligand binding. Here, we review theoretical, simulation and experimental works regarding the regulatory effects of protein-membrane interactions on intercellular receptor-ligand binding mainly from the following aspects: membrane fluctuations, membrane curvature, glycocalyx, and lipid raft. In addition, we discuss biomedical significances and possible research directions to advance the field and highlight the importance of understanding of coupling effects of these factors in pharmaceutical development.
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Affiliation(s)
- Long Li
- Kuang Yaming Honors School and Institute for Brain Sciences, Nanjing University, 210023 Nanjing, China; State Key Laboratory of Nonlinear Mechanics and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, 100190 Beijing, China
| | - Jing Ji
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education Beijing Advanced Innovation Center for Biomedical Engineering School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
| | - Fan Song
- State Key Laboratory of Nonlinear Mechanics and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, 100190 Beijing, China; School of Engineering Science, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Jinglei Hu
- Kuang Yaming Honors School and Institute for Brain Sciences, Nanjing University, 210023 Nanjing, China.
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Acoustic force spectroscopy reveals subtle differences in cellulose unbinding behavior of carbohydrate-binding modules. Proc Natl Acad Sci U S A 2022; 119:e2117467119. [PMID: 36215467 PMCID: PMC9586272 DOI: 10.1073/pnas.2117467119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein adsorption to solid carbohydrate interfaces is critical to many biological processes, particularly in biomass deconstruction. To engineer more-efficient enzymes for biomass deconstruction into sugars, it is necessary to characterize the complex protein-carbohydrate interfacial interactions. A carbohydrate-binding module (CBM) is often associated with microbial surface-tethered cellulosomes or secreted cellulase enzymes to enhance substrate accessibility. However, it is not well known how CBMs recognize, bind, and dissociate from polysaccharides to facilitate efficient cellulolytic activity, due to the lack of mechanistic understanding and a suitable toolkit to study CBM-substrate interactions. Our work outlines a general approach to study the unbinding behavior of CBMs from polysaccharide surfaces using a highly multiplexed single-molecule force spectroscopy assay. Here, we apply acoustic force spectroscopy (AFS) to probe a Clostridium thermocellum cellulosomal scaffoldin protein (CBM3a) and measure its dissociation from nanocellulose surfaces at physiologically relevant, low force loading rates. An automated microfluidic setup and method for uniform deposition of insoluble polysaccharides on the AFS chip surfaces are demonstrated. The rupture forces of wild-type CBM3a, and its Y67A mutant, unbinding from nanocellulose surfaces suggests distinct multimodal CBM binding conformations, with structural mechanisms further explored using molecular dynamics simulations. Applying classical dynamic force spectroscopy theory, the single-molecule unbinding rate at zero force is extrapolated and found to agree with bulk equilibrium unbinding rates estimated independently using quartz crystal microbalance with dissipation monitoring. However, our results also highlight critical limitations of applying classical theory to explain the highly multivalent binding interactions for cellulose-CBM bond rupture forces exceeding 15 pN.
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Liu Y, Wang P, Tian J, Seidi F, Guo J, Zhu W, Xiao H, Song J. Carbohydrate-Binding Modules of Potential Resources: Occurrence in Nature, Function, and Application in Fiber Recognition and Treatment. Polymers (Basel) 2022; 14:1806. [PMID: 35566977 PMCID: PMC9100146 DOI: 10.3390/polym14091806] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/21/2022] [Accepted: 04/24/2022] [Indexed: 02/04/2023] Open
Abstract
Great interests have recently been aroused in the independent associative domain of glycoside hydrolases that utilize insoluble polysaccharides-carbohydrate-binding module (CBM), which responds to binding while the catalytic domain reacts with the substrate. In this mini-review, we first provide a brief introduction on CBM and its subtypes including the classifications, potential sources, structures, and functions. Afterward, the applications of CBMs in substrate recognition based on different types of CBMs have been reviewed. Additionally, the progress of CBMs in paper industry as a new type of environmentally friendly auxiliary agent for fiber treatment is summarized. At last, other applications of CBMs and the future outlook have prospected. Due to the specificity in substrate recognition and diversity in structures, CBM can be a prosperous and promising 'tool' for wood and fiber processing in the future.
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Affiliation(s)
- Yena Liu
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Peipei Wang
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Jing Tian
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Farzad Seidi
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Jiaqi Guo
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Wenyuan Zhu
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Huining Xiao
- Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada;
| | - Junlong Song
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
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Zhao X, Meng X, Ragauskas AJ, Lai C, Ling Z, Huang C, Yong Q. Unlocking the secret of lignin-enzyme interactions: Recent advances in developing state-of-the-art analytical techniques. Biotechnol Adv 2021; 54:107830. [PMID: 34480987 DOI: 10.1016/j.biotechadv.2021.107830] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/07/2021] [Accepted: 08/29/2021] [Indexed: 02/08/2023]
Abstract
Bioconversion of renewable lignocellulosics to produce liquid fuels and chemicals is one of the most effective ways to solve the problem of fossil resource shortage, energy security, and environmental challenges. Among the many biorefinery pathways, hydrolysis of lignocellulosics to fermentable monosaccharides by cellulase is arguably the most critical step of lignocellulose bioconversion. In the process of enzymatic hydrolysis, the direct physical contact between enzymes and cellulose is an essential prerequisite for the hydrolysis to occur. However, lignin is considered one of the most recalcitrant factors hindering the accessibility of cellulose by binding to cellulase unproductively, which reduces the saccharification rate and yield of sugars. This results in high costs for the saccharification of carbohydrates. The various interactions between enzymes and lignin have been explored from different perspectives in literature, and a basic lignin inhibition mechanism has been proposed. However, the exact interaction between lignin and enzyme as well as the recently reported promotion of some types of lignin on enzymatic hydrolysis is still unclear at the molecular level. Multiple analytical techniques have been developed, and fully unlocking the secret of lignin-enzyme interactions would require a continuous improvement of the currently available analytical techniques. This review summarizes the current commonly used advanced research analytical techniques for investigating the interaction between lignin and enzyme, including quartz crystal microbalance with dissipation (QCM-D), surface plasmon resonance (SPR), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), nuclear magnetic resonance (NMR) spectroscopy, fluorescence spectroscopy (FLS), and molecular dynamics (MD) simulations. Interdisciplinary integration of these analytical methods is pursued to provide new insight into the interactions between lignin and enzymes. This review will serve as a resource for future research seeking to develop new methodologies for a better understanding of the basic mechanism of lignin-enzyme binding during the critical hydrolysis process.
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Affiliation(s)
- Xiaoxue Zhao
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China
| | - Xianzhi Meng
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Arthur J Ragauskas
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA; Center for Renewable Carbon, Department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, TN 37996, USA; Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Chenhuan Lai
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China
| | - Zhe Ling
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China
| | - Caoxing Huang
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China.
| | - Qiang Yong
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China.
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Zhang Y, Xu S, Ji F, Hu Y, Gu Z, Xu B. Plant cell wall hydrolysis process reveals structure-activity relationships. PLANT METHODS 2020; 16:147. [PMID: 33292382 PMCID: PMC7640438 DOI: 10.1186/s13007-020-00691-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 10/27/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Recent interest in Populus as a source of renewable energy, combined with its numerous available pretreatment methods, has enabled further research on structural modification and hydrolysis. To improve the biodegradation efficiency of biomass, a better understanding of the relationship between its macroscopic structures and enzymatic process is important. RESULTS This study investigated mutant cell wall structures compared with wild type on a molecular level. Furthermore, a novel insight into the structural dynamics occurring on mutant biomass was assessed in situ and in real time by functional Atomic Force Microscopy (AFM) imaging. High-resolution AFM images confirmed that genetic pretreatment effectively inhibited the production of irregular lignin. The average roughness values of the wild type are 78, 60, and 30 nm which are much higher than that of the mutant cell wall, approximately 10 nm. It is shown that the action of endoglucanases would expose pure crystalline cellulose with more cracks for easier hydrolysis by cellobiohydrolase I (CBHI). Throughout the entire CBHI hydrolytic process, when the average roughness exceeded 3 nm, the hydrolysis mode consisted of a peeling action. CONCLUSION Functional AFM imaging is helpful for biomass structural characterization. In addition, the visualization of the enzymatic hydrolysis process will be useful to explore the cell wall structure-activity relationships.
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Affiliation(s)
- Yanan Zhang
- College of Materials Science and Engineering, Nanjing Tech University, Nanjing, 210016, China.
| | - Shengnan Xu
- College of Materials Science and Engineering, Nanjing Tech University, Nanjing, 210016, China
| | - Fan Ji
- College of Materials Science and Engineering, Nanjing Tech University, Nanjing, 210016, China
| | - Yubing Hu
- National Special Superfine Powder Engineering Research Center of China, Nanjing University of Science & Technology, Nanjing, 210014, China
| | - Zhongwei Gu
- College of Materials Science and Engineering, Nanjing Tech University, Nanjing, 210016, China
| | - Bingqian Xu
- Single Molecule Study Laboratory, College of Engineering and Nanoscale Science and Engineering Center, University of Georgia, Athens, GA, 30602, USA
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Li L, Hu J, Li L, Song F. Binding constant of membrane-anchored receptors and ligands that induce membrane curvatures. SOFT MATTER 2019; 15:3507-3514. [PMID: 30912540 DOI: 10.1039/c8sm02504e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Cell adhesion is crucial for immune response, tissue formation, and cell locomotion. The adhesion process is mediated by the specific binding of membrane-anchored receptor and ligand proteins. These adhesion proteins are in contact with the membranes and may generate curvature, which has been shown for a number of membrane proteins to play an important role in membrane remodeling. An important question remains of whether the local membrane curvatures induced by the adhesion proteins affect their binding. We've performed Monte Carlo simulations of a mesoscopic model for membrane adhesion via the specific binding of curvature-inducing receptors and ligands. We find that the curvatures induced by the adhesion proteins do affect their binding equilibrium constant. We presented a theory that takes into account the membrane deformations and protein-protein interactions due to the induced curvatures, and agrees quantitatively with our simulation results. Our study suggests that the ability to induce membrane curvatures represents a molecular property of the adhesion proteins and should be carefully considered in experimental characterization of the binding affinity.
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Affiliation(s)
- Long Li
- State Key Laboratory of Nonlinear Mechanics (LNM) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, China.
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Li L, Hu J, Xu G, Song F. Binding constant of cell adhesion receptors and substrate-immobilized ligands depends on the distribution of ligands. Phys Rev E 2018; 97:012405. [PMID: 29448355 DOI: 10.1103/physreve.97.012405] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Indexed: 12/16/2022]
Abstract
Cell-cell adhesion and the adhesion of cells to tissues and extracellular matrix, which are pivotal for immune response, tissue development, and cell locomotion, depend sensitively on the binding constant of receptor and ligand molecules anchored on the apposing surfaces. An important question remains of whether the immobilization of ligands affects the affinity of binding with cell adhesion receptors. We have investigated the adhesion of multicomponent membranes to a flat substrate coated with immobile ligands using Monte Carlo simulations of a statistical mesoscopic model with biologically relevant parameters. We find that the binding of the adhesion receptors to ligands immobilized on the substrate is strongly affected by the ligand distribution. In the case of ligand clusters, the receptor-ligand binding constant can be significantly enhanced due to the less translational entropy loss of lipid-raft domains in the model cell membranes upon the formation of additional complexes. For ligands randomly or uniformly immobilized on the substrate, the binding constant is rather decreased since the receptors localized in lipid-raft domains have to pay an energetic penalty in order to bind ligands. Our findings help to understand why cell-substrate adhesion experiments for measuring the impact of lipid rafts on the receptor-ligand interactions led to contradictory results.
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Affiliation(s)
- Long Li
- State Key Laboratory of Nonlinear Mechanics (LNM) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jinglei Hu
- Kuang Yaming Honors School, Nanjing University, Nanjing 210023, China.,Shenzhen Institute of Research, Nanjing University, Shenzhen 518057, China
| | - Guangkui Xu
- School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, China
| | - Fan Song
- State Key Laboratory of Nonlinear Mechanics (LNM) and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.,School of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
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Lakshminarayanan A, Richard M, Davis BG. Studying glycobiology at the single-molecule level. Nat Rev Chem 2018. [DOI: 10.1038/s41570-018-0019-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Zhang Y, Zhang M, Alexander Reese R, Zhang H, Xu B. Real-time single molecular study of a pretreated cellulose hydrolysis mode and individual enzyme movement. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:85. [PMID: 27073415 PMCID: PMC4828794 DOI: 10.1186/s13068-016-0498-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 03/31/2016] [Indexed: 06/05/2023]
Abstract
BACKGROUND The main challenges of large-scale biochemical conversion involve the high costs of cellulolytic enzymes and the inefficiency in enzymatic deconstruction of polysaccharides embedded in the complex structure of the plant cell wall, leading to ongoing interests in studying the predominant mode of enzymatic hydrolysis. In this study, complete enzymatic hydrolysis of pretreated biomass substrates was visualized in situ and in real time by atomic force microscopy (AFM) topography and recognition imaging. Throughout the entire hydrolytic process, a hydrolysis mode for exoglucanase (CBH I) consisting of a peeling action, wherein cellulose microfibrils are peeled from sites on the pretreated cellulose substrate that have cracks sufficiently large for CBH I to immobilize. RESULTS We quantitatively monitored the complete hydrolytic process on pretreated cellulose. The synergetic effect among the different enzymes can accelerate the cellulose hydrolysis rate dramatically. However, the combination of CBH I and β-glucosidases (β-G) exhibited a similar degradation capacity as did whole enzyme (contains the cellobiohydrolases and endoglucanase as its major enzyme components). We developed a comprehensive dynamic analysis for individual cellulase acting on single pretreated cellulose through use of functional AFM topography and recognition imaging. The single crystalline cellulose was divided into different regions based on the cracks on the substrate surface and was observed to either depolymerize or to peel away by the jammed enzyme molecules. After the exfoliation of one region, new cracks were produced for the enzyme molecules to immobilize. The fiber width may have a relationship with the peeling mode of the fibers. We performed a statistical height measure of the generated peaks of the peeled fibers. The height values range from 11 to 24 nm. We assume that the CBH I enzymes stop progressing along the cellulose microfibril when the peeled microfibril height exceeds 11 nm. CONCLUSION The combination of CBH I and β-G can achieve an effective hydrolysis of the pretreated biomass substrates. The single-molecule study of the complete hydrolytic process indicates that the hydrolytic mode involves the peeling of the microfibrils and progressive depolymerization, which depend on the size of the cracks on the surface of the pretreated cellulose microfibrils.
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Affiliation(s)
- Yanan Zhang
- />Single Molecule Study Laboratory, College of Engineering and Nanoscale Science and Engineering Center, University of Georgia, Athens, GA 30602 USA
- />College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016 People’s Republic of China
| | - Mengmeng Zhang
- />Single Molecule Study Laboratory, College of Engineering and Nanoscale Science and Engineering Center, University of Georgia, Athens, GA 30602 USA
| | - R. Alexander Reese
- />Single Molecule Study Laboratory, College of Engineering and Nanoscale Science and Engineering Center, University of Georgia, Athens, GA 30602 USA
| | - Haiqian Zhang
- />College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016 People’s Republic of China
| | - Bingqian Xu
- />Single Molecule Study Laboratory, College of Engineering and Nanoscale Science and Engineering Center, University of Georgia, Athens, GA 30602 USA
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11
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Senapati S, Lindsay S. Recent Progress in Molecular Recognition Imaging Using Atomic Force Microscopy. Acc Chem Res 2016; 49:503-10. [PMID: 26934674 DOI: 10.1021/acs.accounts.5b00533] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Atomic force microscopy (AFM) is an extremely powerful tool in the field of bionanotechnology because of its ability to image single molecules and make measurements of molecular interaction forces with piconewton sensitivity. It works in aqueous media, enabling studies of molecular phenomenon taking place under physiological conditions. Samples can be imaged in their near-native state without any further modifications such as staining or tagging. The combination of AFM imaging with the force measurement added a new feature to the AFM technique, that is, molecular recognition imaging. Molecular recognition imaging enables mapping of specific interactions between two molecules (one attached to the AFM tip and the other to the imaging substrate) by generating simultaneous topography and recognition images (TREC). Since its discovery, the recognition imaging technique has been successfully applied to different systems such as antibody-protein, aptamer-protein, peptide-protein, chromatin, antigen-antibody, cells, and so forth. Because the technique is based on specific binding between the ligand and receptor, it has the ability to detect a particular protein in a mixture of proteins or monitor a biological phenomenon in the native physiological state. One key step for recognition imaging technique is the functionalization of the AFM tips (generally, silicon, silicon nitrides, gold, etc.). Several different functionalization methods have been reported in the literature depending on the molecules of interest and the material of the tip. Polyethylene glycol is routinely used to provide flexibility needed for proper binding as a part of the linker that carries the affinity molecule. Recently, a heterofunctional triarm linker has been synthesized and successfully attached with two different affinity molecules. This novel linker, when attached to AFM tip, helped to detect two different proteins simultaneously from a mixture of proteins using a so-called "two-color" recognition image. Biological phenomena in nature often involve multimolecular interactions, and this new linker could be ideal for studying them using AFM recognition imaging. It also has the potential to be used extensively in the diagnostics technique. This Account includes fundamentals behind AFM recognition imaging, a brief discussion on tip functionalization, recent advancements, and future directions and possibilities.
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Affiliation(s)
- Subhadip Senapati
- Biodesign Institute, ‡Department of Chemistry and Biochemistry, and §Department of
Physics, Arizona State University, Tempe, Arizona 85287, United States
| | - Stuart Lindsay
- Biodesign Institute, ‡Department of Chemistry and Biochemistry, and §Department of
Physics, Arizona State University, Tempe, Arizona 85287, United States
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12
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Xie Y, Wang J, Feng Y. Characterization of Recognition Events between Proteins on a Single Molecule Level with Atomic Force Microscopy. Ind Eng Chem Res 2016. [DOI: 10.1021/acs.iecr.5b03922] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yang Xie
- Key
Laboratory of Biorheological Science and Technology, Ministry of Education
College of Bioengineering, Chongqing University, Chongqing, 400044, P. R. China
| | - Jianhua Wang
- Key
Laboratory of Biorheological Science and Technology, Ministry of Education
College of Bioengineering, Chongqing University, Chongqing, 400044, P. R. China
| | - Yonglai Feng
- Exposure and Biomonitoring
Division, Environmental Health Science and Research Bureau, Health
Canada, Ottawa, Ontario K1A 0K9, Canada
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13
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Li Q, Zhang T, Pan Y, Ciacchi LC, Xu B, Wei G. AFM-based force spectroscopy for bioimaging and biosensing. RSC Adv 2016. [DOI: 10.1039/c5ra22841g] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
AFM-based force spectroscopy shows wide bio-related applications especially for bioimaging and biosensing.
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Affiliation(s)
- Qing Li
- Hybrid Materials Interfaces Group
- Faculty of Production Engineering
- University of Bremen
- D-28359 Bremen
- Germany
| | - Tong Zhang
- Single Molecule Study Laboratory
- College of Engineering and Nanoscale Science and Engineering Center
- University of Georgia
- Altens
- USA
| | - Yangang Pan
- Single Molecule Study Laboratory
- College of Engineering and Nanoscale Science and Engineering Center
- University of Georgia
- Altens
- USA
| | - Lucio Colombi Ciacchi
- Hybrid Materials Interfaces Group
- Faculty of Production Engineering
- University of Bremen
- D-28359 Bremen
- Germany
| | - Bingqian Xu
- Single Molecule Study Laboratory
- College of Engineering and Nanoscale Science and Engineering Center
- University of Georgia
- Altens
- USA
| | - Gang Wei
- Hybrid Materials Interfaces Group
- Faculty of Production Engineering
- University of Bremen
- D-28359 Bremen
- Germany
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14
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Ivanir-Dabora H, Nimerovsky E, Madhu PK, Goldbourt A. Site-Resolved Backbone and Side-Chain Intermediate Dynamics in a Carbohydrate-Binding Module Protein Studied by Magic-Angle Spinning NMR Spectroscopy. Chemistry 2015; 21:10778-85. [DOI: 10.1002/chem.201500856] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Indexed: 12/12/2022]
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15
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Rose M, Babi M, Moran-Mirabal J. The Study of Cellulose Structure and Depolymerization Through Single-Molecule Methods. Ind Biotechnol (New Rochelle N Y) 2015. [DOI: 10.1089/ind.2014.0019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Markus Rose
- Department of Physics and Astronomy, McMaster University, Hamilton, Canada
| | - Mouhanad Babi
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Canada
| | - Jose Moran-Mirabal
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Canada
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