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Cifuente JO, Colleoni C, Kalscheuer R, Guerin ME. Architecture, Function, Regulation, and Evolution of α-Glucans Metabolic Enzymes in Prokaryotes. Chem Rev 2024; 124:4863-4934. [PMID: 38606812 PMCID: PMC11046441 DOI: 10.1021/acs.chemrev.3c00811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
Bacteria have acquired sophisticated mechanisms for assembling and disassembling polysaccharides of different chemistry. α-d-Glucose homopolysaccharides, so-called α-glucans, are the most widespread polymers in nature being key components of microorganisms. Glycogen functions as an intracellular energy storage while some bacteria also produce extracellular assorted α-glucans. The classical bacterial glycogen metabolic pathway comprises the action of ADP-glucose pyrophosphorylase and glycogen synthase, whereas extracellular α-glucans are mostly related to peripheral enzymes dependent on sucrose. An alternative pathway of glycogen biosynthesis, operating via a maltose 1-phosphate polymerizing enzyme, displays an essential wiring with the trehalose metabolism to interconvert disaccharides into polysaccharides. Furthermore, some bacteria show a connection of intracellular glycogen metabolism with the genesis of extracellular capsular α-glucans, revealing a relationship between the storage and structural function of these compounds. Altogether, the current picture shows that bacteria have evolved an intricate α-glucan metabolism that ultimately relies on the evolution of a specific enzymatic machinery. The structural landscape of these enzymes exposes a limited number of core catalytic folds handling many different chemical reactions. In this Review, we present a rationale to explain how the chemical diversity of α-glucans emerged from these systems, highlighting the underlying structural evolution of the enzymes driving α-glucan bacterial metabolism.
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Affiliation(s)
- Javier O. Cifuente
- Instituto
Biofisika (UPV/EHU, CSIC), University of
the Basque Country, E-48940 Leioa, Spain
| | - Christophe Colleoni
- University
of Lille, CNRS, UMR8576-UGSF -Unité de Glycobiologie Structurale
et Fonctionnelle, F-59000 Lille, France
| | - Rainer Kalscheuer
- Institute
of Pharmaceutical Biology and Biotechnology, Heinrich Heine University, 40225 Dusseldorf, Germany
| | - Marcelo E. Guerin
- Structural
Glycobiology Laboratory, Department of Structural and Molecular Biology, Molecular Biology Institute of Barcelona (IBMB), Spanish
National Research Council (CSIC), Barcelona Science Park, c/Baldiri Reixac 4-8, Tower R, 08028 Barcelona, Catalonia, Spain
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2
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Zhang R, Zhu B, Sun C, Li Y, Yang G, Zhao Y, Pan K. UDP-glucose pyrophosphorylase as a target for regulating carbon flux distribution and antioxidant capacity in Phaeodactylum tricornutum. Commun Biol 2023; 6:750. [PMID: 37468748 PMCID: PMC10356853 DOI: 10.1038/s42003-023-05096-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 07/05/2023] [Indexed: 07/21/2023] Open
Abstract
UDP-glucose pyrophosphorylase (UGPase) is a key enzyme for polysaccharide synthesis, and its role in plants and bacteria is well established; however, its functions in unicellular microalgae remain ill-defined. Here, we perform bioinformatics, subcellular localization as well as in vitro and in vivo analyses to elucidate the functions of two UGPs (UGP1 and UGP2) in the model microalga Phaeodactylum tricornutum. Despite differences in amino acid sequence, substrate specificity, and subcellular localization between UGP1 and UGP2, both enzymes can efficiently increase the production of chrysolaminarin (Chrl) or lipids by regulating carbon flux distribution without impairing growth and photosynthesis in transgenic strains. Productivity evaluation indicate that UGP1 play a bigger role in regulating Chrl and lipid production than UGP2. In addition, UGP1 enhance antioxidant capacity, whereas UGP2 is involved in sulfoquinovosyldiacylglycerol (SQDG) synthesis in P. tricornutum. Taken together, the present results suggest that ideal microalgal strains can be developed for the industrial production of Chrl or lipids and lay the foundation for the development of methods to improve oxidative stress tolerance in diatoms.
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Affiliation(s)
- Ruihao Zhang
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao, 266003, China
| | - Baohua Zhu
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao, 266003, China.
- Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266100, China.
| | - Changze Sun
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao, 266003, China
| | - Yun Li
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao, 266003, China
| | - Guanpin Yang
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Yan Zhao
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Kehou Pan
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao, 266003, China.
- Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266100, China.
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3
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Decker D, Aubert J, Wilczynska M, Kleczkowski LA. Exploring Redox Modulation of Plant UDP-Glucose Pyrophosphorylase. Int J Mol Sci 2023; 24:ijms24108914. [PMID: 37240260 DOI: 10.3390/ijms24108914] [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: 04/01/2023] [Revised: 05/10/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
UDP-glucose (UDPG) pyrophosphorylase (UGPase) catalyzes a reversible reaction, producing UDPG, which serves as an essential precursor for hundreds of glycosyltransferases in all organisms. In this study, activities of purified UGPases from sugarcane and barley were found to be reversibly redox modulated in vitro through oxidation by hydrogen peroxide or oxidized glutathione (GSSG) and through reduction by dithiothreitol or glutathione. Generally, while oxidative treatment decreased UGPase activity, a subsequent reduction restored the activity. The oxidized enzyme had increased Km values with substrates, especially pyrophosphate. The increased Km values were also observed, regardless of redox status, for UGPase cysteine mutants (Cys102Ser and Cys99Ser for sugarcane and barley UGPases, respectively). However, activities and substrate affinities (Kms) of sugarcane Cys102Ser mutant, but not barley Cys99Ser, were still prone to redox modulation. The data suggest that plant UGPase is subject to redox control primarily via changes in the redox status of a single cysteine. Other cysteines may also, to some extent, contribute to UGPase redox status, as seen for sugarcane enzymes. The results are discussed with respect to earlier reported details of redox modulation of eukaryotic UGPases and regarding the structure/function properties of these proteins.
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Affiliation(s)
- Daniel Decker
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90187 Umeå, Sweden
| | - Juliette Aubert
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90187 Umeå, Sweden
| | | | - Leszek A Kleczkowski
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90187 Umeå, Sweden
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4
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Silencing 1,3-β-glucan synthase gene promotes total lipid production and changes fatty acids composition by affecting carbon flow distribution in Phaeodactylum tricornutum. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Effects of Magnesium, Pyrophosphate and Phosphonates on Pyrophosphorolytic Reaction of UDP-Glucose Pyrophosphorylase. PLANTS 2022; 11:plants11121611. [PMID: 35736762 PMCID: PMC9230926 DOI: 10.3390/plants11121611] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/05/2022] [Accepted: 06/14/2022] [Indexed: 12/03/2022]
Abstract
UDP-glucose pyrophosphorylase (UGPase) carries a freely reversible reaction, using glucose-1-P and UTP to produce UDP-glucose (UDPG) and pyrophosphate (PPi), with UDPG being essential for glycosylation reactions in all organisms including, e.g., synthesis of sucrose, cellulose and glycoproteins. In the present study, we found that free magnesium (Mg2+) had profound effects on the reverse reaction of purified barley UGPase, and was absolutely required for its activity, with an apparent Km of 0.13 mM. More detailed analyses with varied concentrations of MgPPi allowed us to conclude that it is the MgPPi complex which serves as true substrate for UGPase in its reverse reaction, with an apparent Km of 0.06 mM. Free PPi was an inhibitor in this reaction. Given the key role of PPi in the UGPase reaction, we have also tested possible effects of phosphonates, which are analogs of PPi and phosphate (Pi). Clodronate and etidronate (PPi analogs) had little or no effect on UGPase activity, whereas fosetyl-Al (Pi analog), a known fungicide, acted as effective near-competitive inhibitor versus PPi, with Ki of 0.15 mM. The data are discussed with respect to the role of magnesium in the UGPase reaction and elucidating the use of inhibitors in studies on cellular function of UGPase and related enzymes.
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6
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Liang D, Xiang H, Li S, Wang X, Wang Y. Cloning and heterologous expression of a UDP-sugar-producing pyrophosphorylase gene from the harmful alga Phaeocystis globosa (Prymnesiophyceae) and its possible function in colony formation. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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7
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Zhao L, Ma Z, Yin J, Shi G, Ding Z. Biological strategies for oligo/polysaccharide synthesis: biocatalyst and microbial cell factory. Carbohydr Polym 2021; 258:117695. [PMID: 33593568 DOI: 10.1016/j.carbpol.2021.117695] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 01/20/2021] [Accepted: 01/20/2021] [Indexed: 12/21/2022]
Abstract
Oligosaccharides and polysaccharides constitute the principal components of carbohydrates, which are important biomacromolecules that demonstrate considerable bioactivities. However, the variety and structural complexity of oligo/polysaccharides represent a major challenge for biological and structural explorations. To access structurally defined oligo/polysaccharides, biological strategies using glycoenzyme biocatalysts have shown remarkable synthetic potential attributed to their regioselectivity and stereoselectivity that allow mild, structurally controlled reaction without addition of protecting groups necessary in chemical strategies. This review summarizes recent biotechnological approaches of oligo/polysaccharide synthesis, which mainly includes in vitro enzymatic synthesis and cell factory synthesis. We have discussed the important factors involved in the production of nucleotide sugars. Furthermore, the strategies established in the cell factory and enzymatic syntheses are summarized, and we have highlighted concepts like metabolic flux rebuilding and regulation, enzyme engineering, and route design as important strategies. The research challenges and prospects are also outlined and discussed.
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Affiliation(s)
- Liting Zhao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, 214122, China.
| | - Zhongbao Ma
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, 214122, China.
| | - Jian Yin
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
| | - Guiyang Shi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China.
| | - Zhongyang Ding
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China.
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8
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Minen RI, Martinez MP, Iglesias AA, Figueroa CM. Biochemical characterization of recombinant UDP-sugar pyrophosphorylase and galactinol synthase from Brachypodium distachyon. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 155:780-788. [PMID: 32866791 DOI: 10.1016/j.plaphy.2020.08.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/13/2020] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
Raffinose (Raf) protects plant cells during seed desiccation and under different abiotic stress conditions. The biosynthesis of Raf starts with the production of UDP-galactose by UDP-sugar pyrophosphorylase (USPPase) and continues with the synthesis of galactinol by galactinol synthase (GolSase). Galactinol is then used by Raf synthase to produce Raf. In this work, we report the biochemical characterization of USPPase (BdiUSPPase) and GolSase 1 (BdiGolSase1) from Brachypodium distachyon. The catalytic efficiency of BdiUSPPase was similar with galactose 1-phosphate and glucose 1-phosphate, but 5- to 17-fold lower with other sugar 1-phosphates. The catalytic efficiency of BdiGolSase1 with UDP-galactose was three orders of magnitude higher than with UDP-glucose. A structural model of BdiGolSase1 allowed us to determine the residues putatively involved in the binding of substrates. Among these, we found that Cys261 lies within the putative catalytic pocket. BdiGolSase1 was inactivated by oxidation with diamide and H2O2. The activity of the diamide-oxidized enzyme was recovered by reduction with dithiothreitol or E. coli thioredoxin, suggesting that BdiGolSase1 is redox-regulated.
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Affiliation(s)
- Romina I Minen
- Instituto de Agrobiotecnología del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina
| | - María P Martinez
- Instituto de Agrobiotecnología del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina
| | - Alberto A Iglesias
- Instituto de Agrobiotecnología del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina
| | - Carlos M Figueroa
- Instituto de Agrobiotecnología del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina.
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9
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Differences in the Formation Mechanism of Giant Colonies in Two Phaeocystis globosa Strains. Int J Mol Sci 2020; 21:ijms21155393. [PMID: 32751329 PMCID: PMC7432625 DOI: 10.3390/ijms21155393] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 07/14/2020] [Accepted: 07/27/2020] [Indexed: 12/27/2022] Open
Abstract
Phaeocystis globosa has become one of the primary causes of harmful algal bloom in coastal areas of southern China in recent years, and it poses a serious threat to the marine environment and other activities depending upon on it (e.g., aquaculture, cooling system of power plants), especially in the Beibu Gulf. We found colonies of P. globosa collected form Guangxi (China) were much larger than those obtained from Shantou cultured in lab. To better understand the causes of giant colonies formation, colonial cells collected from P. globosa GX strain (GX-C) and ST strain (ST-C) were separated by filtration. Morphological observations, phylogenetic analyses, rapid light-response curves, fatty acid profiling and transcriptome analyses of two type cells were performed in the laboratory. Although no differences in morphology and 18S rRNA sequences of these cells were observed, the colonies of GX strain (4.7 mm) are 30 times larger than those produced by the ST strain (300 μm). The rapid light-response curve of GX-C was greater than that of ST-C, consistent with the upregulated photosynthetic system, while the fatty acid content of GX-C was lower than that of ST-C, also consistent with the downregulated synthesis of fatty acids and the upregulated degradation of fatty acids. In summary, the increased energy generated by GX-C is allocated to promote the secretion of extracellular polysaccharides for colony formation. We performed a physiological and molecular assessment of the differences between the GX-C and ST-C strains, providing insights into the mechanisms of giant colonies formation in P. globosa.
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10
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Gogoi P, Mordina P, Kanaujia SP. Exploiting the rationale behind substrate recognition by promiscuous thermophilic NDP-sugar pyrophosphorylase for expanding glycorandomization: an in silico study. J Biomol Struct Dyn 2020; 39:6099-6111. [PMID: 32692307 DOI: 10.1080/07391102.2020.1796795] [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: 10/23/2022]
Abstract
The fundamental substrates for protein glycosylation are provided by a group of enzymes known as NDP-sugar pyrophosphorylases (NSPases) which utilize nucleotide triphosphate (NTP) and sugar 1-phosphate to catalyze the formation of nucleotide diphospho-sugar (NDP-sugar). The promiscuous nature of NSPases is often exploited during chemoenzymatic glycorandomization in the pursuit of novel therapeutics. However, till date, the number of inherently promiscuous NSPases reported and the rationale behind their promiscuity is meager. In this study, we have identified a set of NSPases from a hyperthermophilic archaeon Pyrococcus horikoshii OT3 to identify probable candidates for glycorandomization. We identified a set of NSPases that include both substrate-specific and substrate-promiscuous NSPases with a visible predominance of the latter group. The rationale behind the promiscuity (or specificity) vividly lies in the repertoire of amino acid residues that assemble the active site for recognition of the substrate moiety. Furthermore, the absence of a function-specific auxiliary domain promotes substrate promiscuity in NSPases. This study, thus, provides a novel set of thermophilic NSPases that can be employed for chemoenzymatic glycorandomization. More importantly, identification of the residues that render substrate promiscuity (or specificity) would assist in sequence-based rational engineering of NSPases for enhanced glycorandomization. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Prerana Gogoi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Prerana Mordina
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Shankar Prasad Kanaujia
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
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11
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Optimization of nucleotide sugar supply for polysaccharide formation via thermodynamic buffering. Biochem J 2020; 477:341-356. [PMID: 31967651 DOI: 10.1042/bcj20190807] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/16/2019] [Accepted: 12/18/2019] [Indexed: 02/07/2023]
Abstract
Plant polysaccharides (cellulose, hemicellulose, pectin, starch) are either direct (i.e. leaf starch) or indirect products of photosynthesis, and they belong to the most abundant organic compounds in nature. Although each of these polymers is made by a specific enzymatic machinery, frequently in different cell locations, details of their synthesis share certain common features. Thus, the production of these polysaccharides is preceded by the formation of nucleotide sugars catalyzed by fully reversible reactions of various enzymes, mostly pyrophosphorylases. These 'buffering' enzymes are, generally, quite active and operate close to equilibrium. The nucleotide sugars are then used as substrates for irreversible reactions of various polysaccharide-synthesizing glycosyltransferases ('engine' enzymes), e.g. plastidial starch synthases, or plasma membrane-bound cellulose synthase and callose synthase, or ER/Golgi-located variety of glycosyltransferases forming hemicellulose and pectin backbones. Alternatively, the irreversible step might also be provided by a carrier transporting a given immediate precursor across a membrane. Here, we argue that local equilibria, established within metabolic pathways and cycles resulting in polysaccharide production, bring stability to the system via the arrangement of a flexible supply of nucleotide sugars. This metabolic system is itself under control of adenylate kinase and nucleoside-diphosphate kinase, which determine the availability of nucleotides (adenylates, uridylates, guanylates and cytidylates) and Mg2+, the latter serving as a feedback signal from the nucleotide metabolome. Under these conditions, the supply of nucleotide sugars to engine enzymes is stable and constant, and the metabolic process becomes optimized in its load and consumption, making the system steady and self-regulated.
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12
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Palaka BK, Velmurugan Ilavarasi A, Sapam TD, Kotapati KV, Nallala VS, Khan MB, Ampasala DR. Molecular cloning, gene expression analysis, and in silico characterization of UDP-N-acetylglucosamine pyrophosphorylase from Bombyx mori. Biotechnol Appl Biochem 2019; 66:880-899. [PMID: 31397000 DOI: 10.1002/bab.1802] [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: 04/12/2019] [Accepted: 08/07/2019] [Indexed: 12/16/2022]
Abstract
The present study was aimed to explore the molecular and structural features of UDP-N-acetylglucosamine pyrophosphorylase of Bombyx mori (BmUAP), an essential enzyme for chitin synthesis in insects. The BmUAP cDNA sequence was cloned and expression profiles were monitored during the molting and feeding stages of silkworm larvae. The effect of 20-hydroxyecdysone (20E) on BmUAP expression, and on silkworm molting was studied, which revealed that 20E regulates its expression. Multiple sequence alignment of various pyrophosphorylases revealed that the residues N223, G290, N327, and K407 of human UAP (PDB ID: 1JV1) were found to be highly conserved in BmUAP and all other eukaryotic UAPs considered for the study. Phylogenetic analysis inferred that the UAPs possess discrete variations in primary structure among different insect Orders while sharing good identity between species of the Order. The structure of BmUAP was predicted and its interactions with uridine triphosphate, N-acetylglucosamine-1-phosphate, and UDP-N-acetylglucosamine were analyzed. Virtual screening with a library of natural compounds resulted in five potential hits with good binding affinities. On further analysis, these five hits were found to be mimicking substrate and product, in inducing conformational changes in the active site. This work provides crucial information on molecular interactions and structural dynamics of insect UAPs.
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Affiliation(s)
- Bhagath Kumar Palaka
- Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | | | - Tuleshwori Devi Sapam
- Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Kasi Viswanath Kotapati
- Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Venkata Satyanarayana Nallala
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Mohd Babu Khan
- Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Dinakara Rao Ampasala
- Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
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13
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Decker D, Kleczkowski LA. UDP-Sugar Producing Pyrophosphorylases: Distinct and Essential Enzymes With Overlapping Substrate Specificities, Providing de novo Precursors for Glycosylation Reactions. FRONTIERS IN PLANT SCIENCE 2019; 9:1822. [PMID: 30662444 PMCID: PMC6329318 DOI: 10.3389/fpls.2018.01822] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/23/2018] [Indexed: 05/02/2023]
Abstract
Nucleotide sugars are the key precursors for all glycosylation reactions and are required both for oligo- and polysaccharides synthesis and protein and lipid glycosylation. Among all nucleotide sugars, UDP-sugars are the most important precursors for biomass production in nature (e.g., synthesis of cellulose, hemicellulose, and pectins for cell wall production). Several recent studies have already suggested a potential role for UDP-Glc in plant growth and development, and UDP-Glc has also been suggested as a signaling molecule, in addition to its precursor function. In this review, we will cover primary mechanisms of formation of UDP-sugars, by focusing on UDP-sugar metabolizing pyrophosphorylases. The pyrophosphorylases can be divided into three families: UDP-Glc pyrophosphorylase (UGPase), UDP-sugar pyrophosphorylase (USPase), and UDP-N-acetyl glucosamine pyrophosphorylase (UAGPase), which can be distinguished both by their amino acid sequences and by differences in substrate specificity. Substrate specificities of these enzymes are discussed, along with structure-function relationships, based on their crystal structures and homology modeling. Earlier studies with transgenic plants have revealed that each of the pyrophosphorylases is essential for plant survival, and their loss or a decrease in activity results in reproductive impairment. This constitutes a problem when studying exact in vivo roles of the enzymes using classical reverse genetics approaches. Thus, strategies involving the use of specific inhibitors (reverse chemical genetics) are also discussed. Further characterization of the properties/roles of pyrophosphorylases should address fundamental questions dealing with mechanisms and control of carbohydrate synthesis and may allow to identify targets for manipulation of biomass production in plants.
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Affiliation(s)
| | - Leszek A. Kleczkowski
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
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14
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Decker D, Öberg C, Kleczkowski LA. The structure-activity relationship of the salicylimide derived inhibitors of UDP-sugar producing pyrophosphorylases. PLANT SIGNALING & BEHAVIOR 2018; 13:e1507406. [PMID: 30125142 PMCID: PMC6149491 DOI: 10.1080/15592324.2018.1507406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 07/31/2018] [Indexed: 05/18/2023]
Abstract
UDP-sugars are key precursors for biomass production in nature (synthesis of cellulose, hemicellulose, etc.). They are produced de novo by distinct UDP-sugar producing pyrophosphorylases. Studies on the roles of these enzymes using genetic knockouts were hampered by sterility of the mutants and by functional-complementation from related enzyme(s), hindering clear interpretation of the results. In an attempt to override these difficulties, we turned to the reverse chemical genetics approaches to identify compounds which interfere with the activity of those enzymes in vivo. Hit expansion on one of such compounds, a salicylimide derivative, allowed us to identify several inhibitors with a range of activities. The present study provides a structure-activity relationship for these compounds.
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Affiliation(s)
- Daniel Decker
- Department of Plant Physiology, Umeå Plant Science Center, Umeå University, Umeå, Sweden
- CONTACT Leszek A. Kleczkowski Department of Plant Physiology, Umeå Plant Science Center, Umeå University, 90187 Umeå, Sweden
| | - Christopher Öberg
- Laboratories for Chemical Biology Umeå, Department of Chemistry, Umeå University, Umeå, Sweden
| | - Leszek A. Kleczkowski
- Department of Plant Physiology, Umeå Plant Science Center, Umeå University, Umeå, Sweden
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15
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Decker D, Öberg C, Kleczkowski LA. Identification and characterization of inhibitors of UDP-glucose and UDP-sugar pyrophosphorylases for in vivo studies. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 90:1093-1107. [PMID: 28273406 DOI: 10.1111/tpj.13531] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 02/02/2017] [Accepted: 02/23/2017] [Indexed: 05/08/2023]
Abstract
UDP-sugars serve as ultimate precursors in hundreds of glycosylation reactions (e.g. for protein and lipid glycosylation, synthesis of sucrose, cell wall polysaccharides, etc.), underlying an important role of UDP-sugar-producing enzymes in cellular metabolism. However, genetic studies on mechanisms of UDP-sugar formation were frequently hampered by reproductive impairment of the resulting mutants, making it difficult to assess an in vivo role of a given enzyme. Here, a chemical library containing 17 500 compounds was separately screened against purified UDP-glucose pyrophosphorylase (UGPase) and UDP-sugar pyrophosphorylase (USPase), both enzymes representing the primary mechanisms of UDP-sugar formation. Several compounds have been identified which, at 50 μm, exerted at least 50% inhibition of the pyrophosphorylase activity. In all cases, both UGPase and USPase activities were inhibited, probably reflecting common structural features of active sites of these enzymes. One of these compounds (cmp #6), a salicylamide derivative, was found as effective inhibitor of Arabidopsis pollen germination and Arabidopsis cell culture growth. Hit optimization on cmp #6 yielded two analogs (cmp #6D and cmp #6D2), which acted as uncompetitive inhibitors against both UGPase and USPase, and were strong inhibitors in the pollen test, with apparent inhibition constants of less than 1 μm. Their effects on pollen germination were relieved by addition of UDP-glucose and UDP-galactose, suggesting that the inhibitors targeted UDP-sugar formation. The results suggest that cmp #6 and its analogs may represent useful tools to study in vivo roles of the pyrophosphorylases, helping to overcome the limitations of genetic approaches.
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Affiliation(s)
- Daniel Decker
- Department of Plant Physiology, Umeå Plant Science Center, Umeå University, Umeå, 90187, Sweden
| | - Christopher Öberg
- Department of Chemistry, Laboratories for Chemical Biology Umeå, Umeå University, Umeå, 90187, Sweden
| | - Leszek A Kleczkowski
- Department of Plant Physiology, Umeå Plant Science Center, Umeå University, Umeå, 90187, Sweden
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Wahl C, Spiertz M, Elling L. Characterization of a new UDP-sugar pyrophosphorylase from Hordeum vulgare (barley). J Biotechnol 2017; 258:51-55. [PMID: 28347767 DOI: 10.1016/j.jbiotec.2017.03.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 03/21/2017] [Accepted: 03/22/2017] [Indexed: 11/24/2022]
Abstract
The broad substrate spectrum of UDP-sugar pyrophosphorylases from plant salvage pathways is of high interest for the synthesis of expensive nucleotide sugars by straightforward enzyme cascade reactions in combination with monosaccharide kinases. We here present a new UDP-sugar pyrophosphorylase from Hordeum vulgare with favorable biochemical properties like broad pH and temperature tolerances as well as a broad substrate spectrum and high synthesis stability. Enzyme properties were determined and reaction conditions were optimized by high-through-put multiplexed capillary electrophoresis analysis. In combination with a galactokinase UDP-α-d-galactose (UDP-Gal) was efficiently synthesized with a space-time-yield of 17g/L*h for full conversion of 10mM substrate within 20min by 1.2U of each enzyme.
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Affiliation(s)
- Claudia Wahl
- Laboratory for Biomaterials, Institute for Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Markus Spiertz
- Laboratory for Biomaterials, Institute for Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Lothar Elling
- Laboratory for Biomaterials, Institute for Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany.
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17
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Decker D, Kleczkowski LA. Substrate Specificity and Inhibitor Sensitivity of Plant UDP-Sugar Producing Pyrophosphorylases. FRONTIERS IN PLANT SCIENCE 2017; 8:1610. [PMID: 28970843 PMCID: PMC5609113 DOI: 10.3389/fpls.2017.01610] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 09/04/2017] [Indexed: 05/08/2023]
Abstract
UDP-sugars are essential precursors for glycosylation reactions producing cell wall polysaccharides, sucrose, glycoproteins, glycolipids, etc. Primary mechanisms of UDP sugar formation involve the action of at least three distinct pyrophosphorylases using UTP and sugar-1-P as substrates. Here, substrate specificities of barley and Arabidopsis (two isozymes) UDP-glucose pyrophosphorylases (UGPase), Arabidopsis UDP-sugar pyrophosphorylase (USPase) and Arabidopsis UDP-N-acetyl glucosamine pyrophosphorylase2 (UAGPase2) were investigated using a range of sugar-1-phosphates and nucleoside-triphosphates as substrates. Whereas all the enzymes preferentially used UTP as nucleotide donor, they differed in their specificity for sugar-1-P. UGPases had high activity with D-Glc-1-P, but could also react with Fru-1-P and Fru-2-P (Km values over 10 mM). Contrary to an earlier report, their activity with Gal-1-P was extremely low. USPase reacted with a range of sugar-1-phosphates, including D-Glc-1-P, D-Gal-1-P, D-GalA-1-P (Km of 1.3 mM), β-L-Ara-1-P and α-D-Fuc-1-P (Km of 3.4 mM), but not β-L-Fuc-1-P. In contrast, UAGPase2 reacted only with D-GlcNAc-1-P, D-GalNAc-1-P (Km of 1 mM) and, to some extent, D-Glc-1-P (Km of 3.2 mM). Generally, different conformations/substituents at C2, C4, and C5 of the pyranose ring of a sugar were crucial determinants of substrate specificity of a given pyrophosphorylase. Homology models of UDP-sugar binding to UGPase, USPase and UAGPase2 revealed more common amino acids for UDP binding than for sugar binding, reflecting differences in substrate specificity of these proteins. UAGPase2 was inhibited by a salicylate derivative that was earlier shown to affect UGPase and USPase activities, consistent with a common structural architecture of the three pyrophosphorylases. The results are discussed with respect to the role of the pyrophosphorylases in sugar activation for glycosylated end-products.
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Führing JI, Cramer JT, Schneider J, Baruch P, Gerardy-Schahn R, Fedorov R. A quaternary mechanism enables the complex biological functions of octameric human UDP-glucose pyrophosphorylase, a key enzyme in cell metabolism. Sci Rep 2015; 5:9618. [PMID: 25860585 PMCID: PMC5381698 DOI: 10.1038/srep09618] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 03/09/2015] [Indexed: 11/29/2022] Open
Abstract
In mammals, UDP-glucose pyrophosphorylase (UGP) is the only enzyme capable of activating glucose-1-phosphate (Glc-1-P) to UDP-glucose (UDP-Glc), a metabolite located at the intersection of virtually all metabolic pathways in the mammalian cell. Despite the essential role of its product, the molecular basis of UGP function is poorly understood. Here we report the crystal structure of human UGP in complex with its product UDP-Glc. Beyond providing first insight into the active site architecture, we describe the substrate binding mode and intermolecular interactions in the octameric enzyme that are crucial to its activity. Importantly, the quaternary mechanism identified for human UGP in this study may be common for oligomeric sugar-activating nucleotidyltransferases. Elucidating such mechanisms is essential for understanding nucleotide sugar metabolism and opens the perspective for the development of drugs that specifically inhibit simpler organized nucleotidyltransferases in pathogens.
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Affiliation(s)
- Jana Indra Führing
- Institute for Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Johannes Thomas Cramer
- Institute for Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Julia Schneider
- Institute for Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Petra Baruch
- Research Division for Structural Analysis, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Rita Gerardy-Schahn
- Institute for Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Roman Fedorov
- 1] Research Division for Structural Analysis, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany [2] Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
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19
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The UDP-glucose pyrophosphorylase from Giardia lamblia is redox regulated and exhibits promiscuity to use galactose-1-phosphate. Biochim Biophys Acta Gen Subj 2015; 1850:88-96. [DOI: 10.1016/j.bbagen.2014.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 08/26/2014] [Accepted: 10/06/2014] [Indexed: 12/21/2022]
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20
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Kleczkowski LA, Decker D. Sugar Activation for Production of Nucleotide Sugars as Substrates for Glycosyltransferases in Plants. J Appl Glycosci (1999) 2015. [DOI: 10.5458/jag.jag.jag-2015_003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Affiliation(s)
| | - Daniel Decker
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University
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21
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Chen YH, Shen HL, Hsu PJ, Hwang SG, Cheng WH. N-acetylglucosamine-1-P uridylyltransferase 1 and 2 are required for gametogenesis and embryo development in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2014; 55:1977-93. [PMID: 25231969 DOI: 10.1093/pcp/pcu127] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Although N-acetylglucosamine-1-P uridylyltransferase (GlcNAc1pUT) that catalyzes the final step of the hexosamine biosynthetic pathway and is conserved among, organisms, produces UDP-N-acetylglucosamine (UDP-GlcNAc), an essential sugar moiety involved in protein glycosylation and structural polymers, its biological function in plants remains unknown. In this study, two GlcNA.UT genes were characterized in Arabidopsis thaliana. The single mutants glcna.ut1 and glcna.ut2 revealed no obvious phenotype, but their homozygous double mutant was lethal, reflecting the functional redundancy of these genes in being essential for plant growth. Mutant plants, GlcNA.UT1/glcna.ut1 glcna.ut2/ glcna.ut2, obtained from an F2-segregating population following reciprocal crosses of glcna.ut1 with glcna.ut2, displayed shorter siliques and fewer seed sets combined with impaired pollen viability and unfertilized ovules. Genetic analyses further demonstrated that the progeny of the GlcNA.UT1/glcna.ut1 glcna.ut2/glcna.ut2 mutant plants, but not those of the glcna.ut1/glcna.ut1 GlcNA.UT2/glcna.ut2 mutant plants, suffer from the aberrant transmission of (glcna.ut1 glcna.ut2) gametes. In parallel, cell biology analyses revealed a substantial defect in male gametophytes appearing during the late vacuolated or pollen mitosis I stages and that the female gametophyte is arrested during the uninucleate embryo sac stage in GlcNA.UT1/glcna.ut1 glcna.ut2/glcna.ut2 mutant plants. Nevertheless, although the glcna.ut1/glcna.ut1 GlcNA.UT2/glcna.ut2 mutant plants exhibited a normal transmission of (glcna.ut1 glcna.ut2) gametes and gametophytic development, the development of numerous embryos was arrested during the early globular stage within the embryo sacs. Collectively, despite having overlapping functions, the GlcNA.UT genes play an indispensable role in the unique mediation of gametogenesis and embryogenesis.
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Affiliation(s)
- Ya-Huei Chen
- Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Hwei-Ling Shen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Pei-Jung Hsu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - San-Gwang Hwang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan Present address: Department of Horticulture, National Chung Hsing University, Taichung, Taiwan
| | - Wan-Hsing Cheng
- Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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22
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Li N, Wang L, Zhang W, Takechi K, Takano H, Lin X. Overexpression of UDP-glucose pyrophosphorylase from Larix gmelinii enhances vegetative growth in transgenic Arabidopsis thaliana. PLANT CELL REPORTS 2014; 33:779-91. [PMID: 24408396 DOI: 10.1007/s00299-013-1558-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 12/19/2013] [Accepted: 12/20/2013] [Indexed: 05/11/2023]
Abstract
A UDP-glucose pyrophosphorylase gene ( LgUGPase ) was identified from Larix gmelinii, and its function in enhancing vegetative growth and cellulose biosynthesis was confirmed by analyzing transgenic Arabidopsis thaliana overexpressed LgUGPase . UDP-glucose pyrophosphorylase (UGPase), an important regulatory enzyme in carbohydrate metabolism, catalyzes the reversible production of glucose 1-phosphate and the conversion of uridine triphosphate to uridine diphosphate glucose and pyrophosphate. In this study, a larch UGPase (LgUGPase) gene was isolated from Larix gmelinii. The 1,443-bp open reading frame encodes a protein of 480 amino acids with a predicted molecular weight of 53.7 kDa and shows striking sequence similarity to UGPase proteins from Pinus taeda and Picea sitchensis. Semiquantitative reverse transcription-polymerase chain reaction showed that the LgUGPase gene was expressed primarily in the larch stem in addition to its root and leaf. Southern blot analysis indicated that LgUGPase is encoded by two genes in the L. gmelinii genome. Overexpression of LgUGPase enhanced vegetative growth in transgenic Arabidopsis and increased the contents of soluble sugars and cellulose, and thickened parenchyma cell walls. These results revealed that L. gmelinii UGPase participates in sucrose/polysaccharide metabolism and cell wall biosynthesis, suggesting that LgUGPase may be a good candidate gene for improvement of fiber cell development in plants.
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Affiliation(s)
- Ningning Li
- College of Life Sciences, Inner Mongolia University, 235 Daxuexi Road, Hohhot, 010021, China
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23
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Kurnasov OV, Luk HJD, Roberts MF, Stec B. Structure of the inositol-1-phosphate cytidylyltransferase from Thermotoga maritima. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:1808-17. [DOI: 10.1107/s0907444913015278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 06/02/2013] [Indexed: 11/10/2022]
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24
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Fang W, Du T, Raimi OG, Hurtado-Guerrero R, Urbaniak MD, Ibrahim AFM, Ferguson MAJ, Jin C, van Aalten DMF. Genetic and structural validation of Aspergillus fumigatus UDP-N-acetylglucosamine pyrophosphorylase as an antifungal target. Mol Microbiol 2013; 89:479-93. [PMID: 23750903 PMCID: PMC3888555 DOI: 10.1111/mmi.12290] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2013] [Indexed: 01/05/2023]
Abstract
The sugar nucleotide UDP-N-acetylglucosamine (UDP-GlcNAc) is an essential metabolite in both prokaryotes and eukaryotes. In fungi, it is the precursor for the synthesis of chitin, an essential component of the fungal cell wall. UDP-N-acetylglucosamine pyrophosphorylase (UAP) is the final enzyme in eukaryotic UDP-GlcNAc biosynthesis, converting UTP and N-acetylglucosamine-1-phosphate (GlcNAc-1P) to UDP-GlcNAc. As such, this enzyme may provide an attractive target against pathogenic fungi. Here, we demonstrate that the fungal pathogen Aspergillus fumigatus possesses an active UAP (AfUAP1) that shows selectivity for GlcNAc-1P as the phosphosugar substrate. A conditional mutant, constructed by replacing the native promoter of the A. fumigatus uap1 gene with the Aspergillus nidulans alcA promoter, revealed that uap1 is essential for cell survival and important for cell wall synthesis and morphogenesis. The crystal structure of AfUAP1 was determined and revealed exploitable differences in the active site compared with the human enzyme. Thus AfUAP1 could represent a novel antifungal target and this work will assist the future discovery of small molecule inhibitors against this enzyme.
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Affiliation(s)
- Wenxia Fang
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK
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Führing J, Damerow S, Fedorov R, Schneider J, Münster-Kühnel AK, Gerardy-Schahn R. Octamerization is essential for enzymatic function of human UDP-glucose pyrophosphorylase. Glycobiology 2012; 23:426-37. [PMID: 23254995 DOI: 10.1093/glycob/cws217] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Uridine diphosphate-glucose pyrophosphorylase (UGP) occupies a central position in carbohydrate metabolism in all kingdoms of life, since its product uridine diphosphate-glucose (UDP-glucose) is essential in a number of anabolic and catabolic pathways and is a precursor for other sugar nucleotides. Its significance as a virulence factor in protists and bacteria has given momentum to the search for species-specific inhibitors. These attempts are, however, hampered by high structural conservation of the active site architecture. A feature that discriminates UGPs of different species is the quaternary organization. While UGPs in protists are monomers, di- and tetrameric forms exist in bacteria, and crystal structures obtained for the enzyme from yeast and human identified octameric UGPs. These octamers are formed by contacts between highly conserved amino acids in the C-terminal β-helix. Still under debate is the question whether octamerization is required for the functionality of the human enzyme. Here, we used single amino acid replacements in the C-terminal β-helix to interrogate the impact of highly conserved residues on octamer formation and functional activity of human UGP (hUGP). Replacements were guided by the sequence of Arabidopsis thaliana UGP, known to be active as a monomer. Correlating the data obtained in blue native PAGE, size exclusion chromatography and enzymatic activity testing, we prove that the octamer is the active enzyme form. This new insight into structure-function relationships in hUGP does not only improve the understanding of the catalysis of this important enzyme, but in addition broadens the basis for studies aimed at designing drugs that selectively inhibit UGPs from pathogens.
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Affiliation(s)
- Jana Führing
- Institute for Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
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26
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Zhang MZ, Fang JH, Yan X, Liu J, Bao JS, Fransson G, Andersson R, Jansson C, Åman P, Sun C. Molecular insights into how a deficiency of amylose affects carbon allocation--carbohydrate and oil analyses and gene expression profiling in the seeds of a rice waxy mutant. BMC PLANT BIOLOGY 2012; 12:230. [PMID: 23217057 PMCID: PMC3541260 DOI: 10.1186/1471-2229-12-230] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 11/27/2012] [Indexed: 05/19/2023]
Abstract
BACKGROUND Understanding carbon partitioning in cereal seeds is of critical importance to develop cereal crops with enhanced starch yields for food security and for producing specified end-products high in amylose, β-glucan, or fructan, such as functional foods or oils for biofuel applications. Waxy mutants of cereals have a high content of amylopectin and have been well characterized. However, the allocation of carbon to other components, such as β-glucan and oils, and the regulation of the altered carbon distribution to amylopectin in a waxy mutant are poorly understood. In this study, we used a rice mutant, GM077, with a low content of amylose to gain molecular insight into how a deficiency of amylose affects carbon allocation to other end products and to amylopectin. We used carbohydrate analysis, subtractive cDNA libraries, and qPCR to identify candidate genes potentially responsible for the changes in carbon allocation in GM077 seeds. RESULTS Carbohydrate analysis indicated that the content of amylose in GM077 seeds was significantly reduced, while that of amylopectin significantly rose as compared to the wild type BP034. The content of glucose, sucrose, total starch, cell-wall polysaccharides and oil were only slightly affected in the mutant as compared to the wild type. Suppression subtractive hybridization (SSH) experiments generated 116 unigenes in the mutant on the wild-type background. Among the 116 unigenes, three, AGP, ISA1 and SUSIBA2-like, were found to be directly involved in amylopectin synthesis, indicating their possible roles in redirecting carbon flux from amylose to amylopectin. A bioinformatics analysis of the putative SUSIBA2-like binding elements in the promoter regions of the upregulated genes indicated that the SUSIBA2-like transcription factor may be instrumental in promoting the carbon reallocation from amylose to amylopectin. CONCLUSION Analyses of carbohydrate and oil fractions and gene expression profiling on a global scale in the rice waxy mutant GM077 revealed several candidate genes implicated in the carbon reallocation response to an amylose deficiency, including genes encoding AGPase and SUSIBA2-like. We believe that AGP and SUSIBA2 are two promising targets for classical breeding and/or transgenic plant improvement to control the carbon flux between starch and other components in cereal seeds.
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Affiliation(s)
- Ming-Zhou Zhang
- College of Life Science, China JiLiang University, Hangzhou, 310018, China
| | - Jie-Hong Fang
- College of Life Science, China JiLiang University, Hangzhou, 310018, China
| | - Xia Yan
- Department of Plant Biology & Forest Genetics, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, P.O. Box 7080, SE, 75007, Uppsala, Sweden
- Heihe Key Laboratory of Ecohydrology and Integrated River Basin Science, Cold and Arid Regions Environmental and Engineering Institute, Chinese Academy of Sciences, 260 Donggang West Road, Lanzhou, 730000, China
| | - Jun Liu
- College of Life Science, China JiLiang University, Hangzhou, 310018, China
| | - Jin-Song Bao
- Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou, Zhejiang, 310029, China
| | - Gunnel Fransson
- Department of Food Science, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7051, SE, 75007, Uppsala, Sweden
| | - Roger Andersson
- Department of Food Science, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7051, SE, 75007, Uppsala, Sweden
| | - Christer Jansson
- Lawrence Berkeley National Laboratory, Earth Sciences Division, 1 Cyclotron Road, Berkeley, CA, 94720, U.S.A
| | - Per Åman
- Department of Food Science, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7051, SE, 75007, Uppsala, Sweden
| | - Chuanxin Sun
- Department of Plant Biology & Forest Genetics, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, P.O. Box 7080, SE, 75007, Uppsala, Sweden
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27
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Decker D, Meng M, Gornicka A, Hofer A, Wilczynska M, Kleczkowski LA. Substrate kinetics and substrate effects on the quaternary structure of barley UDP-glucose pyrophosphorylase. PHYTOCHEMISTRY 2012; 79:39-45. [PMID: 22552276 DOI: 10.1016/j.phytochem.2012.04.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 03/27/2012] [Accepted: 04/03/2012] [Indexed: 05/08/2023]
Abstract
UDP-Glc pyrophosphorylase (UGPase) is an essential enzyme responsible for production of UDP-Glc, which is used in hundreds of glycosylation reactions involving addition of Glc to a variety of compounds. In this study, barley UGPase was characterized with respect to effects of its substrates on activity and quaternary structure of the protein. Its K(m) values with Glc-1-P and UTP were 0.33 and 0.25 mM, respectively. Besides using Glc-1-P as a substrate, the enzyme had also considerable activity with Gal-1-P; however, the K(m) for Gal-1-P was very high (>10 mM), rendering this reaction unlikely under physiological conditions. UGPase had a relatively broad pH optimum of 6.5-8.5, regardless of the direction of reaction. The enzyme equilibrium constant was 0.4, suggesting slight preference for the Glc-1-P synthesis direction of the reaction. The quaternary structure of the enzyme, studied by Gas-phase Electrophoretic Mobility Macromolecule Analysis (GEMMA), was affected by addition of either single or both substrates in either direction of the reaction, resulting in a shift from UGPase dimers toward monomers, the active form of the enzyme. The substrate-induced changes in quaternary structure of the enzyme may have a regulatory role to assure maximal activity. Kinetics and factors affecting the oligomerization status of UGPase are discussed.
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Affiliation(s)
- Daniel Decker
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90187 Umeå, Sweden
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