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Liu JJ, Hou YK, Wang X, Zhou XT, Yin JY, Nie SP. Recent advances in the biosynthesis of fungal glucan structural diversity. Carbohydr Polym 2024; 329:121782. [PMID: 38286552 DOI: 10.1016/j.carbpol.2024.121782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 12/31/2023] [Accepted: 01/02/2024] [Indexed: 01/31/2024]
Abstract
Glucans are the most abundant class of macromolecule polymers in fungi, which are commonly found in Ascomycota and Basidiomycota. Fungal glucans are not only essential for cell integrity and function but also crucial for the immense industrial interest in high value applications. They present a variety of structural characteristics at the nanoscale due to the high regulation of genes and the involvement of stochastic processes in synthesis. However, although recent findings have demonstrated the genes of glucans synthesis are relatively conserved across diverse fungi, the formation and organization of diverse glucan structures is still unclear in fungi. Here, we summarize the structural features of fungal glucans and the recent developments in the mechanisms of glucans biosynthesis. Furthermore, we propose the engineering strategies of targeted glucan synthesis and point out the remaining challenges in the synthetic process. Understanding the synthesis process of diverse glucans is necessary for tailoring high value glucan towards specific applications. This engineering strategy contributes to enable the sustainable and efficient production of glucan diversity.
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Affiliation(s)
- Jin-Jin Liu
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China
| | - Yu-Ke Hou
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China
| | - Xin Wang
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China
| | - Xing-Tao Zhou
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China
| | - Jun-Yi Yin
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China.
| | - Shao-Ping Nie
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China; Food Laboratory of Zhongyuan, Luo he 462300, Henan, China.
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Boehlein SK, Pfister B, Hennen-Bierwagen TA, Liu C, Ritter M, Hannah LC, Zeeman SC, Resende MFR, Myers AM. Soluble and insoluble α-glucan synthesis in yeast by enzyme suites derived exclusively from maize endosperm. PLANT PHYSIOLOGY 2023; 193:1456-1478. [PMID: 37339339 PMCID: PMC10517254 DOI: 10.1093/plphys/kiad358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 04/28/2023] [Accepted: 05/23/2023] [Indexed: 06/22/2023]
Abstract
Molecular mechanisms that distinguish the synthesis of semi-crystalline α-glucan polymers found in plant starch granules from the synthesis of water-soluble polymers by nonplant species are not well understood. To address this, starch biosynthetic enzymes from maize (Zea mays L.) endosperm were isolated in a reconstituted environment using yeast (Saccharomyces cerevisiae) as a test bed. Ninety strains were constructed containing unique combinations of 11 synthetic transcription units specifying maize starch synthase (SS), starch phosphorylase (PHO), starch branching enzyme (SBE), or isoamylase-type starch debranching enzyme (ISA). Soluble and insoluble branched α-glucans accumulated in varying proportions depending on the enzyme suite, with ISA function stimulating distribution into the insoluble form. Among the SS isoforms, SSIIa, SSIII, and SSIV individually supported the accumulation of glucan polymer. Neither SSI nor SSV alone produced polymers; however, synergistic effects demonstrated that both isoforms can stimulate α-glucan accumulation. PHO did not support α-glucan production by itself, but it had either positive or negative effects on polymer content depending on which SS or a combination thereof was present. The complete suite of maize enzymes generated insoluble particles resembling native starch granules in size, shape, and crystallinity. Ultrastructural analysis revealed a hierarchical assembly starting with subparticles of approximately 50 nm diameter that coalesce into discrete structures of approximately 200 nm diameter. These are assembled into semi-crystalline α-glucan superstructures up to 4 μm in length filling most of the yeast cytosol. ISA was not essential for the formation of such particles, but their abundance was increased dramatically by ISA presence.
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Affiliation(s)
- Susan K Boehlein
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32601, USA
| | - Barbara Pfister
- Institute of Molecular Plant Biology, ETH Zurich, Zurich 8092, Switzerland
| | - Tracie A Hennen-Bierwagen
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Chun Liu
- Institute of Molecular Plant Biology, ETH Zurich, Zurich 8092, Switzerland
| | - Maximilian Ritter
- Institute for Building Materials, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zurich 8093, Switzerland
| | - L Curtis Hannah
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32601, USA
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, ETH Zurich, Zurich 8092, Switzerland
| | - Marcio F R Resende
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32601, USA
| | - Alan M Myers
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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Liu C, Pfister B, Osman R, Ritter M, Heutinck A, Sharma M, Eicke S, Fischer-Stettler M, Seung D, Bompard C, Abt MR, Zeeman SC. LIKE EARLY STARVATION 1 and EARLY STARVATION 1 promote and stabilize amylopectin phase transition in starch biosynthesis. SCIENCE ADVANCES 2023; 9:eadg7448. [PMID: 37235646 DOI: 10.1126/sciadv.adg7448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 04/19/2023] [Indexed: 05/28/2023]
Abstract
Starch, the most abundant carbohydrate reserve in plants, primarily consists of the branched glucan amylopectin, which forms semi-crystalline granules. Phase transition from a soluble to an insoluble form depends on amylopectin architecture, requiring a compatible distribution of glucan chain lengths and a branch-point distribution. Here, we show that two starch-bound proteins, LIKE EARLY STARVATION 1 (LESV) and EARLY STARVATION 1 (ESV1), which have unusual carbohydrate-binding surfaces, promote the phase transition of amylopectin-like glucans, both in a heterologous yeast system expressing the starch biosynthetic machinery and in Arabidopsis plants. We propose a model wherein LESV serves as a nucleating role, with its carbohydrate-binding surfaces helping align glucan double helices to promote their phase transition into semi-crystalline lamellae, which are then stabilized by ESV1. Because both proteins are widely conserved, we suggest that protein-facilitated glucan crystallization may be a general and previously unrecognized feature of starch biosynthesis.
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Affiliation(s)
- Chun Liu
- Institute of Molecular Plant Biology, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland
| | - Barbara Pfister
- Institute of Molecular Plant Biology, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland
| | - Rayan Osman
- Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Maximilian Ritter
- Institute for Building Materials, ETH Zurich, Stefano-Franscini-Platz 3, 8093 Zurich, Switzerland
| | - Arvid Heutinck
- Institute of Molecular Plant Biology, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland
| | - Mayank Sharma
- Institute of Molecular Plant Biology, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland
| | - Simona Eicke
- Institute of Molecular Plant Biology, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland
| | | | - David Seung
- Institute of Molecular Plant Biology, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland
| | - Coralie Bompard
- Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Melanie R Abt
- Institute of Molecular Plant Biology, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland
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