1
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Lu Y, Mehling M, Huan S, Bai L, Rojas OJ. Biofabrication with microbial cellulose: from bioadaptive designs to living materials. Chem Soc Rev 2024. [PMID: 38864385 DOI: 10.1039/d3cs00641g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Nanocellulose is not only a renewable material but also brings functions that are opening new technological opportunities. Here we discuss a special subset of this material, in its fibrillated form, which is produced by aerobic microorganisms, namely, bacterial nanocellulose (BNC). BNC offers distinct advantages over plant-derived counterparts, including high purity and high degree of polymerization as well as crystallinity, strength, and water-holding capacity, among others. More remarkably, beyond classical fermentative protocols, it is possible to grow BNC on non-planar interfaces, opening new possibilities in the assembly of advanced bottom-up structures. In this review, we discuss the recent advances in the area of BNC-based biofabrication of three-dimensional (3D) designs by following solid- and soft-material templating. These methods are shown as suitable platforms to achieve bioadaptive constructs comprising highly interlocked biofilms that can be tailored with precise control over nanoscale morphological features. BNC-based biofabrication opens applications that are not possible by using traditional manufacturing routes, including direct ink writing of hydrogels. This review emphasizes the critical contributions of microbiology, colloid and surface science, as well as additive manufacturing in achieving bioadaptive designs from living matter. The future impact of BNC biofabrication is expected to take advantage of material and energy integration, residue utilization, circularity and social latitudes. Leveraging existing infrastructure, the scaleup of biofabrication routes will contribute to a new generation of advanced materials rooted in exciting synergies that combine biology, chemistry, engineering and material sciences.
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Affiliation(s)
- Yi Lu
- Bioproducts Institute, Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
| | - Marina Mehling
- Bioproducts Institute, Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
| | - Siqi Huan
- Key Laboratory of Bio-Based Material Science and Technology (Ministry of Education), Northeast Forestry University, Harbin 150040, China.
| | - Long Bai
- Key Laboratory of Bio-Based Material Science and Technology (Ministry of Education), Northeast Forestry University, Harbin 150040, China.
| | - Orlando J Rojas
- Bioproducts Institute, Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
- Department of Chemistry, The University of British Columbia, Vancouver, BC, V6T 1Z1, Canada.
- Department of Wood Science, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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2
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Yu A, Beck M, Merzendorfer H, Yang Q. Advances in understanding insect chitin biosynthesis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 164:104058. [PMID: 38072083 DOI: 10.1016/j.ibmb.2023.104058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/17/2023]
Abstract
Chitin, a natural polymer of N-acetylglucosamine chains, is a principal component of the apical extracellular matrix in arthropods. Chitin microfibrils serve as structural components of natural biocomposites present in the extracellular matrix of a variety of invertebrates including sponges, molluscs, nematodes, fungi and arthropods. In this review, we summarize the frontier advances of insect chitin synthesis. More specifically, we focus on the chitin synthase (CHS), which catalyzes the key biosynthesis step. CHS is also known as an attractive insecticidal target in that this enzyme is absent in mammals, birds or plants. As no insect chitin synthase structure have been reported so far, we review recent studies on glycosyltransferase domain structures derived from fungi and oomycetes, which are conserved in CHS from all species containing chitin. Auxiliary proteins, which coordinate with CHS in chitin biosynthesis and assembly, are also discussed.
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Affiliation(s)
- Ailing Yu
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Marius Beck
- Department of Chemistry-Biology, University of Siegen, Siegen, Germany
| | - Hans Merzendorfer
- Department of Chemistry-Biology, University of Siegen, Siegen, Germany.
| | - Qing Yang
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
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3
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Cui FJ, Fu X, Sun L, Zan XY, Meng LJ, Sun WJ. Recent insights into glucans biosynthesis and engineering strategies in edible fungi. Crit Rev Biotechnol 2023:1-18. [PMID: 38105513 DOI: 10.1080/07388551.2023.2289341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 04/21/2023] [Indexed: 12/19/2023]
Abstract
Fungal α/β-glucans have significant importance in cellular functions including cell wall structure, host-pathogen interactions and energy storage, and wide application in high-profile fields, including food, nutrition, and pharmaceuticals. Fungal species and their growth/developmental stages result in a diversity of glucan contents, structures and bioactivities. Substantial progresses have been made to elucidate the fine structures and functions, and reveal the potential molecular synthesis pathway of fungal α/β-glucans. Herein, we review the current knowledge about the biosynthetic machineries, including: precursor UDP-glucose synthesis, initiation, elongation/termination and remodeling of α/β-glucan chains, and molecular regulation to maximally produce glucans in edible fungi. This review would provide future perspectives to biosynthesize the targeted glucans and reveal the catalytic mechanism of enzymes associated with glucan synthesis, including: UDP-glucose pyrophosphate phosphorylases (UGP), glucan synthases, and glucanosyltransferases in edible fungi.
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Affiliation(s)
- Feng-Jie Cui
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, P. R. China
- Jiangxi Provincial Engineering and Technology Center for Food Additives Bio-production, Dexing, P. R. China
| | - Xin Fu
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, P. R. China
| | - Lei Sun
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, P. R. China
| | - Xin-Yi Zan
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, P. R. China
| | - Li-Juan Meng
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, P. R. China
| | - Wen-Jing Sun
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, P. R. China
- Jiangxi Provincial Engineering and Technology Center for Food Additives Bio-production, Dexing, P. R. China
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4
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Jayachandran D, Banerjee S, Chundawat SPS. Plant cellulose synthase membrane protein isolation directly from Pichia pastoris protoplasts, liposome reconstitution, and its enzymatic characterization. Protein Expr Purif 2023:106309. [PMID: 37211149 DOI: 10.1016/j.pep.2023.106309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/17/2023] [Accepted: 05/18/2023] [Indexed: 05/23/2023]
Abstract
Cellulose is synthesized by a plant cell membrane-integrated processive glycosyltransferase (GT) called cellulose synthase (CesA). Since only a few of these plant CesAs have been purified and characterized to date, there are huge gaps in our mechanistic understanding of these enzymes. The biochemistry and structural biology studies of CesAs are currently hampered by challenges associated with their expression and extraction at high yields. To aid in understanding CesA reaction mechanisms and to provide a more efficient CesA extraction method, two putative plant CesAs - PpCesA5 from Physcomitrella patens and PttCesA8 from Populus tremula x tremuloides that are involved in primary and secondary cell wall formation in plants were expressed using Pichia pastoris as an expression host. We developed a protoplast-based membrane protein extraction approach to directly isolate these membrane-bound enzymes, as confirmed by immunoblotting and mass spectrometry-based analyses. Our method gives 3-4-fold higher purified protein yield than the standard cell homogenization protocol. Our method resulted in liposome reconstituted CesA5 and CesA8 enzymes with similar Michaelis-Menten kinetic constants, Km = 167 μM, 108 μM and Vmax = 7.88 × 10-5 μmol/min, 4.31 × 10-5 μmol/min, respectively, in concurrence with the previous studies for enzymes isolated using the standard protocol. Taken together, these results suggest that CesAs involved in primary and secondary cell wall formation can be expressed and purified using a simple and more efficient extraction method. This protocol could help isolate enzymes that unravel the mechanism of native and engineered cellulose synthase complexes involved in plant cell wall biosynthesis.
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Affiliation(s)
- Dharanidaran Jayachandran
- Department of Chemical and Biochemical Engineering, Rutgers-The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Shoili Banerjee
- Department of Chemical and Biochemical Engineering, Rutgers-The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Shishir P S Chundawat
- Department of Chemical and Biochemical Engineering, Rutgers-The State University of New Jersey, Piscataway, NJ, 08854, USA.
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5
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Amrabadi T, Jalilnejad E, Ojagh SMA, Vahabzadeh F. Application of TOPSIS algorithm in describing bacterial cellulose-based composite hydrogel performance in incorporating methylene blue as a model drug. Sci Rep 2023; 13:2755. [PMID: 36797363 PMCID: PMC9935555 DOI: 10.1038/s41598-023-29865-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/11/2023] [Indexed: 02/18/2023] Open
Abstract
A multi-component hydrogel was developed using bacterial cellulose, alginate, and gelatin with the aid of glycerol as trihydric alcohol which participates in re-distribution of hydrogen bonds in the test system. FTIR, XRD, SEM, and TGA as instrumental techniques were used to structurally characterize the physical/chemical properties of the formed composite hydrogel. By using an exponential equation, swelling behavior of the hydrogel was evaluated. By incorporating a model drug (methylene blue-MB) in the formed hydrogel, experiments were directed to study release characteristics of the MB where the medium solution for the release was prepared at four different pHs. The maximum cumulative drug release at pH 2.8, 6, 7.4, and 9 were 42.8, 63, 80, and 84.5%, respectively. Data fitting process was carried out using five kinetic models (Korsmeyer-Peppas, Higuchi, Hopfenberg, zero-order, and first-order equations) and the preferred kinetic model at each pH was estimated by applying TOPSIS algorithmic technique. The adsorption capacity of the hydrogel in relation to MB was determined while thermodynamic properties of this relationship were quantified ([Formula: see text] and [Formula: see text]). The results of the present study were in favor of the potential usage of the developed composite hydrogel in drug delivery systems.
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Affiliation(s)
- Touraj Amrabadi
- grid.411368.90000 0004 0611 6995Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
| | - Elham Jalilnejad
- Department of Chemical Engineering, Urmia University of Technology, Urmia, West Azerbaijan, Iran.
| | - Seyed Mohammad Amin Ojagh
- grid.411368.90000 0004 0611 6995Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran ,grid.14709.3b0000 0004 1936 8649Department of Chemistry, McGill University, Montreal, QC Canada
| | - Farzaneh Vahabzadeh
- grid.411368.90000 0004 0611 6995Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
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6
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Purushotham P, Ho R, Yu L, Fincher GB, Bulone V, Zimmer J. Mechanism of mixed-linkage glucan biosynthesis by barley cellulose synthase-like CslF6 (1,3;1,4)-β-glucan synthase. SCIENCE ADVANCES 2022; 8:eadd1596. [PMID: 36367939 PMCID: PMC9651860 DOI: 10.1126/sciadv.add1596] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
Mixed-linkage (1,3;1,4)-β-glucans, which are widely distributed in cell walls of the grasses, are linear glucose polymers containing predominantly (1,4)-β-linked glucosyl units interspersed with single (1,3)-β-linked glucosyl units. Their distribution in cereal grains and unique structures are important determinants of dietary fibers that are beneficial to human health. We demonstrate that the barley cellulose synthase-like CslF6 enzyme is sufficient to synthesize a high-molecular weight (1,3;1,4)-β-glucan in vitro. Biochemical and cryo-electron microscopy analyses suggest that CslF6 functions as a monomer. A conserved "switch motif" at the entrance of the enzyme's transmembrane channel is critical to generate (1,3)-linkages. There, a single-point mutation markedly reduces (1,3)-linkage formation, resulting in the synthesis of cellulosic polysaccharides. Our results suggest that CslF6 monitors the orientation of the nascent polysaccharide's second or third glucosyl unit. Register-dependent interactions with these glucosyl residues reposition the polymer's terminal glucosyl unit to form either a (1,3)- or (1,4)-β-linkage.
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Affiliation(s)
- Pallinti Purushotham
- Howard Hughes Medical Institute, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, 480 Ray C. Hunt Dr., Charlottesville, VA 22908, USA
| | - Ruoya Ho
- Howard Hughes Medical Institute, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, 480 Ray C. Hunt Dr., Charlottesville, VA 22908, USA
| | - Long Yu
- Adelaide Glycomics, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia
- School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia
| | - Geoffrey B. Fincher
- School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia
| | - Vincent Bulone
- Adelaide Glycomics, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia
- School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology, and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm, SE-10691, Sweden
| | - Jochen Zimmer
- Howard Hughes Medical Institute, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, 480 Ray C. Hunt Dr., Charlottesville, VA 22908, USA
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7
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Chen W, Cao P, Liu Y, Yu A, Wang D, Chen L, Sundarraj R, Yuchi Z, Gong Y, Merzendorfer H, Yang Q. Structural basis for directional chitin biosynthesis. Nature 2022; 610:402-408. [PMID: 36131020 PMCID: PMC9556331 DOI: 10.1038/s41586-022-05244-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022]
Abstract
Chitin, the most abundant aminopolysaccharide in nature, is an extracellular polymer consisting of N-acetylglucosamine (GlcNAc) units1. The key reactions of chitin biosynthesis are catalysed by chitin synthase2-4, a membrane-integrated glycosyltransferase that transfers GlcNAc from UDP-GlcNAc to a growing chitin chain. However, the precise mechanism of this process has yet to be elucidated. Here we report five cryo-electron microscopy structures of a chitin synthase from the devastating soybean root rot pathogenic oomycete Phytophthora sojae (PsChs1). They represent the apo, GlcNAc-bound, nascent chitin oligomer-bound, UDP-bound (post-synthesis) and chitin synthase inhibitor nikkomycin Z-bound states of the enzyme, providing detailed views into the multiple steps of chitin biosynthesis and its competitive inhibition. The structures reveal the chitin synthesis reaction chamber that has the substrate-binding site, the catalytic centre and the entrance to the polymer-translocating channel that allows the product polymer to be discharged. This arrangement reflects consecutive key events in chitin biosynthesis from UDP-GlcNAc binding and polymer elongation to the release of the product. We identified a swinging loop within the chitin-translocating channel, which acts as a 'gate lock' that prevents the substrate from leaving while directing the product polymer into the translocating channel for discharge to the extracellular side of the cell membrane. This work reveals the directional multistep mechanism of chitin biosynthesis and provides a structural basis for inhibition of chitin synthesis.
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Affiliation(s)
- Wei Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Peng Cao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Yuansheng Liu
- School of Bioengineering, Dalian University of Technology, Dalian, China
| | - Ailing Yu
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Dong Wang
- School of Bioengineering, Dalian University of Technology, Dalian, China
| | - Lei Chen
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Rajamanikandan Sundarraj
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Zhiguang Yuchi
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Yong Gong
- Center for Multi-disciplinary Research, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China.
| | - Hans Merzendorfer
- Department of Chemistry and Biology, School of Science and Technology, University of Siegen, Siegen, Germany
| | - Qing Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.
- School of Bioengineering, Dalian University of Technology, Dalian, China.
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8
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Ren Z, Chhetri A, Guan Z, Suo Y, Yokoyama K, Lee SY. Structural basis for inhibition and regulation of a chitin synthase from Candida albicans. Nat Struct Mol Biol 2022; 29:653-664. [PMID: 35788183 DOI: 10.1038/s41594-022-00791-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 05/20/2022] [Indexed: 11/09/2022]
Abstract
Chitin is an essential component of the fungal cell wall. Chitin synthases (Chss) catalyze chitin formation and translocation across the membrane and are targets of antifungal agents, including nikkomycin Z and polyoxin D. Lack of structural insights into the action of these inhibitors on Chs has hampered their further development to the clinic. We present the cryo-EM structures of Chs2 from Candida albicans (CaChs2) in the apo, substrate-bound, nikkomycin Z-bound, and polyoxin D-bound states. CaChs2 adopts a unique domain-swapped dimer configuration where a conserved motif in the domain-swapped region controls enzyme activity. CaChs2 has a dual regulation mechanism where the chitin translocation tunnel is closed by the extracellular gate and plugged by a lipid molecule in the apo state to prevent non-specific leak. Analyses of substrate and inhibitor binding provide insights into the chemical logic of Chs inhibition, which can guide Chs-targeted antifungal development.
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Affiliation(s)
- Zhenning Ren
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Abhishek Chhetri
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Ziqiang Guan
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Yang Suo
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Kenichi Yokoyama
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA.
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA.
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9
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Maloney FP, Kuklewicz J, Corey RA, Bi Y, Ho R, Mateusiak L, Pardon E, Steyaert J, Stansfeld PJ, Zimmer J. Structure, substrate recognition and initiation of hyaluronan synthase. Nature 2022; 604:195-201. [PMID: 35355017 PMCID: PMC9358715 DOI: 10.1038/s41586-022-04534-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 02/08/2022] [Indexed: 11/09/2022]
Abstract
Hyaluronan is an acidic heteropolysaccharide comprising alternating N-acetylglucosamine and glucuronic acid sugars that is ubiquitously expressed in the vertebrate extracellular matrix1. The high-molecular-mass polymer modulates essential physiological processes in health and disease, including cell differentiation, tissue homeostasis and angiogenesis2. Hyaluronan is synthesized by a membrane-embedded processive glycosyltransferase, hyaluronan synthase (HAS), which catalyses the synthesis and membrane translocation of hyaluronan from uridine diphosphate-activated precursors3,4. Here we describe five cryo-electron microscopy structures of a viral HAS homologue at different states during substrate binding and initiation of polymer synthesis. Combined with biochemical analyses and molecular dynamics simulations, our data reveal how HAS selects its substrates, hydrolyses the first substrate to prime the synthesis reaction, opens a hyaluronan-conducting transmembrane channel, ensures alternating substrate polymerization and coordinates hyaluronan inside its transmembrane pore. Our research suggests a detailed model for the formation of an acidic extracellular heteropolysaccharide and provides insights into the biosynthesis of one of the most abundant and essential glycosaminoglycans in the human body.
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Affiliation(s)
- Finn P Maloney
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jeremi Kuklewicz
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Robin A Corey
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Yunchen Bi
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Ruoya Ho
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Lukasz Mateusiak
- Laboratory for In Vivo Cellular and Molecular Imaging, ICMI-BEFY, Vrije Universiteit Brussel, Brussels, Belgium
| | - Els Pardon
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, VUB, Brussels, Belgium
| | - Jan Steyaert
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, VUB, Brussels, Belgium
| | - Phillip J Stansfeld
- School of Life Sciences and Department of Chemistry, University of Warwick, Coventry, UK
| | - Jochen Zimmer
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA.
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10
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Chhetri A, Loksztejn A, Yokoyama K. Quantitative Characterization of the Amount and Length of (1,3)-β-d-glucan for Functional and Mechanistic Analysis of Fungal (1,3)-β-d-glucan Synthase. Bio Protoc 2021; 11:e3995. [PMID: 34124296 DOI: 10.21769/bioprotoc.3995] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 02/04/2021] [Accepted: 03/01/2021] [Indexed: 11/02/2022] Open
Abstract
(1,3)-β-d-Glucan synthase (GS) is an essential enzyme for fungal cell wall biosynthesis that catalyzes the synthesis of (1,3)-β-d-glucan, a major and vital component of the cell wall. GS is a proven target of antifungal antibiotics including FDA-approved echinocandin derivatives; however, the function and mechanism of GS remain largely uncharacterized due to the absence of informative activity assays. Previously, a radioactive assay and reducing end modification have been used to characterize GS activity. The radioactive assay determines only the total amount of glucan formed through glucose incorporation and does not report the length of the polymers produced. The glucan length has been characterized by reducing end modification, but this method is unsuitable for mechanistic studies due to the very high detection limit of millimolar amounts and the labor intensiveness of the technique. Consequently, fundamental aspects of GS catalysis, such as the polymer length specificity, remain ambiguous. We have developed a size exclusion chromatography (SEC)-based method that allows detailed functional and mechanistic characterization of GS. The approach harnesses the pH-dependent solubility of (1,3)-β-d-glucan, where (1,3)-β-d-glucan forms water-soluble random coils under basic pH conditions, and can be analyzed by SEC using pulsed amperometric detection (PAD) and radioactivity counting (RC). This approach allows quantitative characterization of the total amount and length of glucan produced by GS with minimal workup and a d-glucose (Glc) detection limit of ~100 pmol. Consequently, this approach was successfully used for the kinetic characterization of GS, providing the first detailed mechanistic insight into GS catalysis. Due to its sensitivity, the assay is applicable to the characterization of GS from any fungi and can be adapted to study other polysaccharide synthases.
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Affiliation(s)
- Abhishek Chhetri
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina, USA
| | - Anna Loksztejn
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina, USA
| | - Kenichi Yokoyama
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina, USA
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11
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Abstract
Extracellular polysaccharides and glycoproteins of pathogenic bacteria assist in adherence, autoaggregation, biofilm formation, and host immune system evasion. As a result, considerable research in the field of glycobiology is dedicated to study the composition and function of glycans associated with virulence, as well as the enzymes involved in their biosynthesis with the aim to identify novel antibiotic targets. Especially, insights into the enzyme mechanism, substrate binding, and transition-state structures are valuable as a starting point for rational inhibitor design. An intriguing aspect of enzymes that generate or process polysaccharides and glycoproteins is the level of processivity. The existence of enzymatic processivity reflects the need for regulation of the final glycan/glycoprotein length and structure, depending on the role they perform. In this Review, we describe the currently reported examples of various processive enzymes involved in polymerization and transfer of sugar moieties, predominantly in bacterial pathogens, with a focus on the biochemical methods, to showcase the importance of studying processivity for understanding the mechanism.
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Affiliation(s)
- Liubov Yakovlieva
- Stratingh Institute for Chemistry, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Marthe T. C. Walvoort
- Stratingh Institute for Chemistry, University of Groningen, 9747 AG Groningen, The Netherlands
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12
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Chhetri A, Loksztejn A, Nguyen H, Pianalto KM, Kim MJ, Hong J, Alspaugh JA, Yokoyama K. Length Specificity and Polymerization Mechanism of (1,3)-β-d-Glucan Synthase in Fungal Cell Wall Biosynthesis. Biochemistry 2020; 59:682-693. [PMID: 31899625 DOI: 10.1021/acs.biochem.9b00896] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
(1,3)-β-d-Glucan synthase (GS) catalyzes formation of the linear (1,3)-β-d-glucan in the fungal cell wall and is a target of clinically approved antifungal antibiotics. The catalytic subunit of GS, FKS protein, does not exhibit significant sequence homology to other glycosyltransferases, and thus, significant ambiguity about its catalytic mechanism remains. One of the major technical barriers in studying GS is the absence of activity assay methods that allow characterization of the lengths and amounts of (1,3)-β-d-glucan due to its poor solubility in water and organic solvents. Here, we report a successful development of a novel GS activity assay based on size-exclusion chromatography coupled with pulsed amperometric detection and radiation counting (SEC-PAD-RC), which allows for the simultaneous characterization of the amount and length of the polymer product. The assay revealed that the purified yeast GS produces glucan with a length of 6550 ± 760 mer, consistent with the reported degree of polymerization of (1,3)-β-d-glucan isolated from intact cells. Pre-steady state kinetic analysis revealed a highly efficient but rate-determining chain elongation rate of 51.5 ± 9.8 s-1, which represents the first observation of chain elongation by a nucleotide-sugar-dependent polysaccharide synthase. Coupling the SEC-PAD-RC method with substrate analogue mechanistic probes provided the first unambiguous evidence that GS catalyzes non-reducing end polymerization. On the basis of these observations, we propose a detailed model for the catalytic mechanism of GS. The approaches described here can be used to determine the mechanism of catalysis of other polysaccharide synthases.
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Affiliation(s)
- Abhishek Chhetri
- Department of Biochemistry , Duke University School of Medicine , Durham , North Carolina 27710 , United States
| | - Anna Loksztejn
- Department of Biochemistry , Duke University School of Medicine , Durham , North Carolina 27710 , United States
| | - Hai Nguyen
- Department of Biochemistry , Duke University School of Medicine , Durham , North Carolina 27710 , United States
| | - Kaila M Pianalto
- Department of Medicine , Duke University School of Medicine , Durham , North Carolina 27710 , United States
| | - Mi Jung Kim
- Department of Chemistry , Duke University , Durham , North Carolina 27708-0354 , United States
| | - Jiyong Hong
- Department of Chemistry , Duke University , Durham , North Carolina 27708-0354 , United States
| | - J Andrew Alspaugh
- Department of Medicine , Duke University School of Medicine , Durham , North Carolina 27710 , United States
| | - Kenichi Yokoyama
- Department of Biochemistry , Duke University School of Medicine , Durham , North Carolina 27710 , United States.,Department of Chemistry , Duke University , Durham , North Carolina 27708-0354 , United States
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13
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Yang H, McManus J, Oehme D, Singh A, Yingling YG, Tien M, Kubicki JD. Simulations of Cellulose Synthesis Initiation and Termination in Bacteria. J Phys Chem B 2019; 123:3699-3705. [PMID: 30983346 DOI: 10.1021/acs.jpcb.9b02433] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The processivity of cellulose synthesis in bacterial cellulose synthase (CESA) was investigated using molecular dynamics simulations and the hybrid quantum mechanics and molecular mechanics approach. Our results suggested that cellulose synthesis in bacterial CESA can be initiated with H2O molecules. The chain length or degree of polymerization (DOP) of the product cellulose is related to the affinity of the cellulose chain to the transmembrane tunnel of the enzyme. This opens up the possibility of generating mutants that would produce cellulose chains with desired chain lengths that could have applications in the biofuel and textile fields that depend on the DOP of cellulose chains.
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Affiliation(s)
| | | | - Daniel Oehme
- Department of Geological Sciences , University of Texas at El Paso , El Paso , Texas , United States
| | - Abhishek Singh
- Department of Materials Science and Engineering , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Yaroslava G Yingling
- Department of Materials Science and Engineering , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | | | - James D Kubicki
- Department of Geological Sciences , University of Texas at El Paso , El Paso , Texas , United States
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14
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Allen KN, Imperiali B. Structural and mechanistic themes in glycoconjugate biosynthesis at membrane interfaces. Curr Opin Struct Biol 2019; 59:81-90. [PMID: 31003021 DOI: 10.1016/j.sbi.2019.03.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 12/29/2022]
Abstract
Peripheral and integral membrane proteins feature in stepwise assembly of complex glycans and glycoconjugates. Catalysis on membrane-bound substrates features challenges with substrate solubility and active-site accessibility. However, advantages in enzyme and substrate orientation and control of lateral membrane diffusion provide order to the multistep processes. Recent glycosyltransferase (GT) studies show that substrate diversity is met by the selection of folds which do not converge upon a common mechanism. Examples of polyprenol phosphate phosphoglycosyl transferases (PGTs) highlight that divergent fold families catalyze the same reaction with different mechanisms. Lipid A biosynthesis enzymes illustrate that variations on the robust Rossmann fold allow substrate diversity. Improved understanding of GT and PGT structure and function holds promise for better function prediction and improvement of therapeutic inhibitory ligands.
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Affiliation(s)
- Karen N Allen
- Department of Chemistry, Boston University, Boston, MA 02215, United States; Program in Biomolecular Pharmacology, Boston University School of Medicine, Boston, MA 02118, United States.
| | - Barbara Imperiali
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
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15
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Tajima H, Penttilä PA, Imai T, Yamamoto K, Yuguchi Y. Observation of in vitro cellulose synthesis by bacterial cellulose synthase with time-resolved small angle X-ray scattering. Int J Biol Macromol 2019; 130:765-777. [PMID: 30831170 DOI: 10.1016/j.ijbiomac.2019.02.167] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/25/2019] [Accepted: 02/28/2019] [Indexed: 10/27/2022]
Abstract
Cellulose synthase is the enzyme that produces cellulose in the living organisms like plant, and has two functions: polymerizing glucose residues (polymerization) and assembling these polymerized molecules into a crystalline microfibril with a "cellulose I" crystallographic structure (crystallization). Many studies, however, have shown that an in vitro reaction of cellulose synthase produces aggregates of a non-native crystallographic structure "cellulose II", despite the remaining polymerizing activity. This is partial denaturation or loss of crystallization function in cellulose synthase, which needs to be resolved to reconstitute its native activity. To this end, we aimed to clarify the process of cellulose II formation by bacterial cellulose synthase in vitro, using in situ small angle X-ray scattering (SAXS). An increase in scattering specific to synthesis was observed around two distinct regions of q (0.2-0.4 nm-1 and <0.1 nm-1) by time-resolved SAXS measurement. The scattering at higher q-region appears prior to lower-q scattering at beginning of the reaction, indicating the existence of smaller primitive aggregations at the initiation stage. This study demonstrates the use of in situ SAXS measurement to decipher the dynamics of biosynthesized cellulose chains, which is a remarkable example of polymer assembly in ambient conditions.
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Affiliation(s)
- Hirotaka Tajima
- Research Institute for Sustainable Humanosphere (RISH), Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Paavo A Penttilä
- Research Institute for Sustainable Humanosphere (RISH), Kyoto University, Uji, Kyoto 611-0011, Japan; Science Division/Large-Scale Structures Group, Institut Laue-Langevin (ILL), 71 avenue des Martyrs, 38042 Grenoble, France
| | - Tomoya Imai
- Research Institute for Sustainable Humanosphere (RISH), Kyoto University, Uji, Kyoto 611-0011, Japan.
| | - Kyoko Yamamoto
- Faculty of Engineering, Osaka Electro-Communication University, 18-8 Hatsucho, Neyagawa, Osaka 572-8530, Japan
| | - Yoshiaki Yuguchi
- Faculty of Engineering, Osaka Electro-Communication University, 18-8 Hatsucho, Neyagawa, Osaka 572-8530, Japan.
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16
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McManus JB, Wilson L, Yang H, Kubicki JD, Tien M. Kinetic analysis of cellulose synthase of Gluconacetobacter hansenii in whole cells and in purified form. Enzyme Microb Technol 2018; 119:24-29. [PMID: 30243383 DOI: 10.1016/j.enzmictec.2018.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 08/21/2018] [Indexed: 10/28/2022]
Abstract
The Gram-negative bacterium, Gluconacetobacter hansenii, has been long studied and is a model for cellulose synthesis. It produces cellulose, using the enzyme AcsA-AcsB, of exceptionally high crystallinity in comparison to the cellulose of higher plants. We determined the rate of cellulose synthesis in whole cells measured as moles of glucose incorporated into cellulose per second per mole of enzyme. This was determined by quantifying the rate of cellulose synthesis (over a short time span, such that the enzyme concentration is not changing due to cell growth) and the amount of enzyme in the whole cell by quantitative western blotting. We found that the whole cell rate of 24 s-1 is much faster than the kcat, measured from steady-state kinetic analysis, of 1.7 s-1. Our whole cell rates are consistent with previous studies using microscopy. We postulate that the rationale for this difference is the presence of an alternative in vivo priming mechanism. This in turn can increase the rate of initiation, which we previously postulated to be the rate-limiting step in catalysis.
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Affiliation(s)
- John B McManus
- Department of Biochemistry and Molecular Biology, 305 South Frear, University Park, The Pennsylvania State University, PA, 16802, USA
| | - Liza Wilson
- Department of Biology, University Park, The Pennsylvania State University, PA, 16802, USA
| | - Hui Yang
- Department of Biology, University Park, The Pennsylvania State University, PA, 16802, USA
| | - James D Kubicki
- Department of Geological Sciences, University of Texas at El Paso, El Paso, TX, 79968, USA
| | - Ming Tien
- Department of Biochemistry and Molecular Biology, 305 South Frear, University Park, The Pennsylvania State University, PA, 16802, USA.
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