1
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Hobbs JK, Boraston AB. The structure of a pectin-active family 1 polysaccharide lyase from the marine bacterium Pseudoalteromonas fuliginea. Acta Crystallogr F Struct Biol Commun 2024; 80:142-147. [PMID: 38935515 PMCID: PMC11229556 DOI: 10.1107/s2053230x2400596x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Accepted: 06/19/2024] [Indexed: 06/29/2024] Open
Abstract
Pseudoalteromonas fuliginea sp. PS47 is a recently identified marine bacterium that has extensive enzymatic machinery to metabolize polysaccharides, including a locus that targets pectin-like substrates. This locus contains a gene (locus tag EU509_03255) that encodes a pectin-degrading lyase, called PfPL1, that belongs to polysaccharide lyase family 1 (PL1). The 2.2 Å resolution X-ray crystal structure of PfPL1 reveals the compact parallel β-helix fold of the PL1 family. The back side of the core parallel β-helix opposite to the active site is a meandering set of five α-helices joined by lengthy loops. A comparison of the active site with those of other PL1 enzymes suggests a catalytic mechanism that is independent of metal ions, such as Ca2+, but that substrate recognition may require metal ions. Overall, this work provides the first structural insight into a pectinase of marine origin and the first structure of a PL1 enzyme in subfamily 2.
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Affiliation(s)
- Joanne K. Hobbs
- Department of Biochemistry and MicrobiologyUniversity of VictoriaPO Box 1700 STN CSCVictoriaBCV8W 2Y2Canada
| | - Alisdair B. Boraston
- Department of Biochemistry and MicrobiologyUniversity of VictoriaPO Box 1700 STN CSCVictoriaBCV8W 2Y2Canada
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2
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Li W, Li P, Deng Y, Zhang Z, Situ J, Huang J, Li M, Xi P, Jiang Z, Kong G. Litchi aspartic protease LcAP1 enhances plant resistance via suppressing cell death triggered by the pectate lyase PlPeL8 from Peronophythora litchii. THE NEW PHYTOLOGIST 2024; 242:2682-2701. [PMID: 38622771 DOI: 10.1111/nph.19755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 03/20/2024] [Indexed: 04/17/2024]
Abstract
Plant cell death is regulated in plant-pathogen interactions. While some aspartic proteases (APs) participate in regulating programmed cell death or defense responses, the defense functions of most APs remain largely unknown. Here, we report on a virulence factor, PlPeL8, which is a pectate lyase found in the hemibiotrophic pathogen Peronophythora litchii. Through in vivo and in vitro assays, we confirmed the interaction between PlPeL8 and LcAP1 from litchi, and identified LcAP1 as a positive regulator of plant immunity. PlPeL8 induced cell death associated with NbSOBIR1 and NbMEK2. The 11 conserved residues of PlPeL8 were essential for inducing cell death and enhancing plant susceptibility. Twenty-three LcAPs suppressed cell death induced by PlPeL8 in Nicotiana benthamiana depending on their interaction with PlPeL8. The N-terminus of LcAP1 was required for inhibiting PlPeL8-triggered cell death and susceptibility. Furthermore, PlPeL8 led to higher susceptibility in NbAPs-silenced N. benthamiana than the GUS-control. Our results indicate the crucial roles of LcAP1 and its homologs in enhancing plant resistance via suppression of cell death triggered by PlPeL8, and LcAP1 represents a promising target for engineering disease resistance. Our study provides new insights into the role of plant cell death in the arms race between plants and hemibiotrophic pathogens.
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Affiliation(s)
- Wen Li
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Peng Li
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Yizhen Deng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, 510642, China
| | - Zijing Zhang
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Junjian Situ
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Ji Huang
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Minhui Li
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Pinggen Xi
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Zide Jiang
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
| | - Guanghui Kong
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China
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3
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Xiao Y, Sun G, Yu Q, Gao T, Zhu Q, Wang R, Huang S, Han Z, Cervone F, Yin H, Qi T, Wang Y, Chai J. A plant mechanism of hijacking pathogen virulence factors to trigger innate immunity. Science 2024; 383:732-739. [PMID: 38359129 DOI: 10.1126/science.adj9529] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 12/22/2023] [Indexed: 02/17/2024]
Abstract
Polygalacturonase-inhibiting proteins (PGIPs) interact with pathogen-derived polygalacturonases to inhibit their virulence-associated plant cell wall-degrading activity but stimulate immunity-inducing oligogalacturonide production. Here we show that interaction between Phaseolus vulgaris PGIP2 (PvPGIP2) and Fusarium phyllophilum polygalacturonase (FpPG) enhances substrate binding, resulting in inhibition of the enzyme activity of FpPG. This interaction promotes FpPG-catalyzed production of long-chain immunoactive oligogalacturonides, while diminishing immunosuppressive short oligogalacturonides. PvPGIP2 binding creates a substrate binding site on PvPGIP2-FpPG, forming a new polygalacturonase with boosted substrate binding activity and altered substrate preference. Structure-based engineering converts a putative PGIP that initially lacks FpPG-binding activity into an effective FpPG-interacting protein. These findings unveil a mechanism for plants to transform pathogen virulence activity into a defense trigger and provide proof of principle for engineering PGIPs with broader specificity.
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Affiliation(s)
- Yu Xiao
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guangzheng Sun
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs), Nanjing Agricultural University, Nanjing 210095, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing 210095, China
| | - Qiangsheng Yu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Teng Gao
- Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qinsheng Zhu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs), Nanjing Agricultural University, Nanjing 210095, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing 210095, China
| | - Rui Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs), Nanjing Agricultural University, Nanjing 210095, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing 210095, China
| | - Shijia Huang
- School of Life Sciences, Westlake University, Hangzhou 310024, China
| | - Zhifu Han
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China
| | - Felice Cervone
- Dipartimento di Biologia e Biotecnologie "C. Darwin," Sapienza, University of Rome, Piazzale Aldo Moro, 00185 Roma, Italy
| | - Heng Yin
- Dalian Engineering Research Center for Carbohydrate Agricultural Preparations, Liaoning Provincial Key Laboratory of Carbohydrates, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Tiancong Qi
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs), Nanjing Agricultural University, Nanjing 210095, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing 210095, China
| | - Jijie Chai
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
- School of Life Sciences, Westlake University, Hangzhou 310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China
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4
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Iobbi V, Donadio G, Lanteri AP, Maggi N, Kirchmair J, Parisi V, Minuto G, Copetta A, Giacomini M, Bisio A, De Tommasi N, Drava G. Targeted metabolite profiling of Salvia rosmarinus Italian local ecotypes and cultivars and inhibitory activity against Pectobacterium carotovorum subsp. carotovorum. FRONTIERS IN PLANT SCIENCE 2024; 15:1164859. [PMID: 38390298 PMCID: PMC10883066 DOI: 10.3389/fpls.2024.1164859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 01/12/2024] [Indexed: 02/24/2024]
Abstract
Introduction The development of agriculture in terms of sustainability and low environmental impact is, at present, a great challenge, mainly in underdeveloped and marginal geographical areas. The Salvia rosmarinus "Eretto Liguria" ecotype is widespread in Liguria (Northwest Italy), and farmers commonly use it by for cuttings and for marketing. In the present study, this ecotype was characterized in comparison with other cultivars from the same geographical region and Campania (Southern Italy), with a view to application and registration processes for the designation of protected geographical indications. Moreover, the possibility of using the resulting biomass after removing cuttings or fronds as a source of extracts and pure compounds to be used as phytosanitary products in organic farming was evaluated. Specifically, the potential of rosemary extracts and pure compounds to prevent soft rot damage was then tested. Methods A targeted NMR metabolomic approach was employed, followed by multivariate analysis, to characterize the rosemary accessions. Bacterial soft rot assay and disk diffusion test were carried out to evaluate the activity of extracts and isolated compounds against Pectobacterium carotovorum subsp. carotovorum. Enzymatic assay was performed to measure the in vitro inhibition of the pectinase activity produced by the selected pathogen. Molecular docking simulations were used to explore the possible interaction of the selected compounds with the pectinase enzymes. Results and Discussion The targeted metabolomic analysis highlighted those different geographical locations can influence the composition and abundance of bioactive metabolites in rosemary extracts. At the same time, genetic factors are important when a single geographical area is considered. Self-organizing maps (SOMs) showed that the accessions of "Eretto Liguria" appeared well characterized when compared to the others and had a good content in specialized metabolites, particularly carnosic acid. Soft rotting Enterobacteriaceae belonging to the Pectobacterium genus represent a serious problem in potato culture. Even though rosemary methanolic extracts showed a low antibacterial activity against a strain of Pectobacterium carotovorum subsp. carotovorum in the disk diffusion test, they showed ability in reducing the soft rot damage induced by the bacterium on potato tissue. 7-O-methylrosmanol, carnosol and isorosmanol appeared to be the most active components. In silico studies indicated that these abietane diterpenoids may interact with P. carotovorum subsp. carotovorum pectate lyase 1 and endo-polygalacturonase, thus highlighting these rosemary components as starting points for the development of agents able to prevent soft rot progression.
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Affiliation(s)
- Valeria Iobbi
- Department of Pharmacy, University of Genova, Genova, Italy
| | | | - Anna Paola Lanteri
- Plant Pathology Laboratory, Section Microbiology and Molecular Biology, Centro di Sperimentazione e Assistenza Agricola (CeRSAA), Albenga, Italy
| | - Norbert Maggi
- Department of Informatics, Bioengineering, Robotics and System Science, University of Genova, Genova, Italy
| | - Johannes Kirchmair
- Department of Pharmaceutical Sciences, Division of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | | | - Giovanni Minuto
- Plant Pathology Laboratory, Section Microbiology and Molecular Biology, Centro di Sperimentazione e Assistenza Agricola (CeRSAA), Albenga, Italy
| | - Andrea Copetta
- Research Centre For Vegetable and Ornamental Crops (CREA), Sanremo, Italy
| | - Mauro Giacomini
- Department of Informatics, Bioengineering, Robotics and System Science, University of Genova, Genova, Italy
| | - Angela Bisio
- Department of Pharmacy, University of Genova, Genova, Italy
| | | | - Giuliana Drava
- Department of Pharmacy, University of Genova, Genova, Italy
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5
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Lian MQ, Furusawa G, Teh AH. Trigalacturonate-producing pectate lyase PelQ1 from Saccharobesus litoralis with unique exolytic activity. Carbohydr Res 2024; 536:109045. [PMID: 38340525 DOI: 10.1016/j.carres.2024.109045] [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: 11/03/2023] [Revised: 01/05/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024]
Abstract
PelQ1 from Saccharobesus litoralis is a Ca2+-dependent pectate lyase belonging to the polysaccharide lyase family 1 (PL1). Although being an endolytic enzyme, it degraded polygalacturonate into predominantly unsaturated trimer in an exolytic manner with delayed production of dimer, tetramer and pentamer. The enzyme harbours a C-terminal domain from the carbohydrate-binding module family 13 (CBM13), whose presence facilitated the production of dimer. PelQ1's homology model showed that it possessed a well-conserved catalytic cleft, with R232 acting as the general base and R203 as the general acid. Structural comparison with DcPelC, a similar trimer-generating pectate lyase from Dickeya chrysanthemi EC16, implied that both enzymes' catalytic clefts encompassed at least eight subsites, i.e. -5 to +3. The unequal distribution of the subsites between the reducing and non-reducing ends of the cleavage site might be responsible for the exolytic generation of the trimer. As all but the -1, +1 and + 2 subsites could accommodate methylated galacturonate, this subclass of PL1 pectate lyases may function to help break up methylated pectin.
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Affiliation(s)
- Melissa Qianyue Lian
- Centre for Chemical Biology, Universiti Sains Malaysia, Sains@USM, 11900, Penang, Malaysia; USM-RIKEN International Centre for Ageing Science (URICAS), Universiti Sains Malaysia, 11800, Penang, Malaysia
| | - Go Furusawa
- Centre for Chemical Biology, Universiti Sains Malaysia, Sains@USM, 11900, Penang, Malaysia
| | - Aik-Hong Teh
- Centre for Chemical Biology, Universiti Sains Malaysia, Sains@USM, 11900, Penang, Malaysia; USM-RIKEN International Centre for Ageing Science (URICAS), Universiti Sains Malaysia, 11800, Penang, Malaysia.
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6
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Pandey S, Berger BW, Acharya R. Structural Analyses of Substrate-pH Activity Pairing Observed across Diverse Polysaccharide Lyases. Biochemistry 2023; 62:2775-2790. [PMID: 37620757 DOI: 10.1021/acs.biochem.3c00321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
Anionic polysaccharides found in nature are functionally and structurally diverse, and so are the polysaccharide lyases (PLs) that catalyze their degradation. Atomic superposition of various PL folds according to their cleavable substrate structure confirms the occurrence of structural convergence at PL active sites. This suggests that various PL folds have emerged to cleave a particular class of anionic polysaccharide during the course of evolution. Whereas the structural and mechanistic similarity of PL active site has been highlighted in earlier studies, a detailed understanding regarding functional properties of this catalytic convergence remains an open question, especially the role of extrinsic factors such as pH in the context of substrate binding and catalysis. Our earlier structural and functional work on pH directed multisubstrate specificity of Smlt1473 inspired us to regroup PLs according to substrate type to analyze the pH dependence of their catalytic activity. Interestingly, we find that particular groups of substrates are cleaved in a particular pH range (acidic/neutral/basic) irrespective of PL fold, boosting the idea of functional convergence as well. On the basis of this observation, we set out to define structurally and computationally the key constituents of an active site among PL families. This study delineates the structural determinants of conserved "substrate-pH activity pairing" within and between PL families.
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Affiliation(s)
- Shubhant Pandey
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, 752050 Odisha, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094 Maharashtra, India
| | - Bryan W Berger
- Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Rudresh Acharya
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, 752050 Odisha, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094 Maharashtra, India
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7
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Safran J, Ung V, Bouckaert J, Habrylo O, Molinié R, Fontaine JX, Lemaire A, Voxeur A, Pilard S, Pau-Roblot C, Mercadante D, Pelloux J, Sénéchal F. The specificity of pectate lyase VdPelB from Verticilium dahliae is highlighted by structural, dynamical and biochemical characterizations. Int J Biol Macromol 2023; 231:123137. [PMID: 36639075 DOI: 10.1016/j.ijbiomac.2023.123137] [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: 11/03/2022] [Revised: 12/29/2022] [Accepted: 01/01/2023] [Indexed: 01/12/2023]
Abstract
Pectins, complex polysaccharides and major components of the plant primary cell wall, can be degraded by pectate lyases (PLs). PLs cleave glycosidic bonds of homogalacturonans (HG), the main pectic domain, by β-elimination, releasing unsaturated oligogalacturonides (OGs). To understand the catalytic mechanism and structure/function of these enzymes, we characterized VdPelB from Verticillium dahliae. We first solved the crystal structure of VdPelB at 1.2 Å resolution showing that it is a right-handed parallel β-helix structure. Molecular dynamics (MD) simulations further highlighted the dynamics of the enzyme in complex with substrates that vary in their degree of methylesterification, identifying amino acids involved in substrate binding and cleavage of non-methylesterified pectins. We then biochemically characterized wild type and mutated forms of VdPelB. Pectate lyase VdPelB was most active on non-methylesterified pectins, at pH 8.0 in presence of Ca2+ ions. The VdPelB-G125R mutant was most active at pH 9.0 and showed higher relative activity compared to native enzyme. The OGs released by VdPelB differed to that of previously characterized PLs, showing its peculiar specificity in relation to its structure. OGs released from Verticillium-partially tolerant and sensitive flax cultivars differed which could facilitate the identification VdPelB-mediated elicitors of defence responses.
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Affiliation(s)
- Josip Safran
- UMR INRAE 1158 BioEcoAgro - Biologie des Plantes et Innovation, Université de Picardie Jules Verne, UFR des Sciences, 33 Rue St Leu, 80039 Amiens, France
| | - Vanessa Ung
- School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Julie Bouckaert
- Unité de Glycobiologie Structurale et Fonctionnelle (UGSF), UMR8576 CNRS, Université de Lille, Campus CNRS Haute Borne, Avenue de Halley, 59658, Villeneuve d'Ascq, France
| | - Olivier Habrylo
- UMR INRAE 1158 BioEcoAgro - Biologie des Plantes et Innovation, Université de Picardie Jules Verne, UFR des Sciences, 33 Rue St Leu, 80039 Amiens, France
| | - Roland Molinié
- UMR INRAE 1158 BioEcoAgro - Biologie des Plantes et Innovation, Université de Picardie Jules Verne, UFR des Sciences, 33 Rue St Leu, 80039 Amiens, France
| | - Jean-Xavier Fontaine
- UMR INRAE 1158 BioEcoAgro - Biologie des Plantes et Innovation, Université de Picardie Jules Verne, UFR des Sciences, 33 Rue St Leu, 80039 Amiens, France
| | - Adrien Lemaire
- UMR INRAE 1158 BioEcoAgro - Biologie des Plantes et Innovation, Université de Picardie Jules Verne, UFR des Sciences, 33 Rue St Leu, 80039 Amiens, France
| | - Aline Voxeur
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Serge Pilard
- Plateforme Analytique, Université de Picardie Jules Verne, 33 Rue St Leu, 80039 Amiens, France
| | - Corinne Pau-Roblot
- UMR INRAE 1158 BioEcoAgro - Biologie des Plantes et Innovation, Université de Picardie Jules Verne, UFR des Sciences, 33 Rue St Leu, 80039 Amiens, France
| | - Davide Mercadante
- School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Jérôme Pelloux
- UMR INRAE 1158 BioEcoAgro - Biologie des Plantes et Innovation, Université de Picardie Jules Verne, UFR des Sciences, 33 Rue St Leu, 80039 Amiens, France.
| | - Fabien Sénéchal
- UMR INRAE 1158 BioEcoAgro - Biologie des Plantes et Innovation, Université de Picardie Jules Verne, UFR des Sciences, 33 Rue St Leu, 80039 Amiens, France.
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8
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Kalmbach L, Bourdon M, Belevich I, Safran J, Lemaire A, Heo JO, Otero S, Blob B, Pelloux J, Jokitalo E, Helariutta Y. Putative pectate lyase PLL12 and callose deposition through polar CALS7 are necessary for long-distance phloem transport in Arabidopsis. Curr Biol 2023; 33:926-939.e9. [PMID: 36805125 DOI: 10.1016/j.cub.2023.01.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 11/12/2022] [Accepted: 01/19/2023] [Indexed: 02/18/2023]
Abstract
In plants, the phloem distributes photosynthetic products for metabolism and storage over long distances. It relies on specialized cells, the sieve elements, which are enucleated and interconnected through large so-called sieve pores in their adjoining cell walls. Reverse genetics identified PECTATE LYASE-LIKE 12 (PLL12) as critical for plant growth and development. Using genetic complementations, we established that PLL12 is required exclusively late during sieve element differentiation. Structural homology modeling, enzyme inactivation, and overexpression suggest a vital role for PLL12 in sieve-element-specific pectin remodeling. While short distance symplastic diffusion is unaffected, the pll12 mutant is unable to accommodate sustained plant development due to an incapacity to accommodate increasing hydraulic demands on phloem long-distance transport as the plant grows-a defect that is aggravated when combined with another sieve-element-specific mutant callose synthase 7 (cals7). Establishing CALS7 as a specific sieve pore marker, we investigated the subcellular dynamics of callose deposition in the developing sieve plate. Using fluorescent CALS7 then allowed identifying structural defects in pll12 sieve pores that are moderate at the cellular level but become physiologically relevant due to the serial arrangement of sieve elements in the sieve tube. Overall, pectin degradation through PLL12 appears subtle in quantitative terms. We therefore speculate that PLL12 may act as a regulator to locally remove homogalacturonan, thus potentially enabling further extracellular enzymes to access and modify the cell wall during sieve pore maturation.
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Affiliation(s)
- Lothar Kalmbach
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK.
| | - Matthieu Bourdon
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Ilya Belevich
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Josip Safran
- UMR INRAE 1158 BioEcoAgro, BIOPI Biologie des Plantes et Innovation, Université de Picardie, 33 Rue St Leu, 80039 Amiens, France
| | - Adrien Lemaire
- UMR INRAE 1158 BioEcoAgro, BIOPI Biologie des Plantes et Innovation, Université de Picardie, 33 Rue St Leu, 80039 Amiens, France
| | - Jung-Ok Heo
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK; Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Sofia Otero
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Bernhard Blob
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Jérôme Pelloux
- UMR INRAE 1158 BioEcoAgro, BIOPI Biologie des Plantes et Innovation, Université de Picardie, 33 Rue St Leu, 80039 Amiens, France
| | - Eija Jokitalo
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Ykä Helariutta
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK; Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland.
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9
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Structure of an Alkaline Pectate Lyase and Rational Engineering with Improved Thermo-Alkaline Stability for Efficient Ramie Degumming. Int J Mol Sci 2022; 24:ijms24010538. [PMID: 36613981 PMCID: PMC9820310 DOI: 10.3390/ijms24010538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 12/31/2022] Open
Abstract
Alkaline pectate lyases have biotechnological applications in plant fiber processing, such as ramie degumming. Previously, we characterized an alkaline pectate lyase from Bacillus clausii S10, named BacPelA, which showed potential for enzymatic ramie degumming because of its high cleavage activity toward methylated pectins in alkaline conditions. However, BacPelA displayed poor thermo-alkaline stability. Here, we report the 1.78 Å resolution crystal structure of BacPelA in apo form. The enzyme has the characteristic right-handed β-helix fold of members of the polysaccharide lyase 1 family and shows overall structural similarity to them, but it displays some differences in the details of the secondary structure and Ca2+-binding site. On the basis of the structure, 10 sites located in flexible regions and showing high B-factor and positive ΔTm values were selected for mutation, aiming to improve the thermo-alkaline stability of the enzyme. Following site-directed saturation mutagenesis and screening, mutants A238C, R150G, and R216H showed an increase in the T5015 value at pH 10.0 of 3.0 °C, 6.5 °C, and 7.0 °C, respectively, compared with the wild-type enzyme, interestingly accompanied by a 24.5%, 46.6%, and 61.9% increase in activity. The combined mutant R150G/R216H/A238C showed an 8.5 °C increase in the T5015 value at pH 10.0, and an 86.1% increase in the specific activity at 60 °C, with approximately doubled catalytic efficiency, compared with the wild-type enzyme. Moreover, this mutant retained 86.2% activity after incubation in ramie degumming conditions (4 h, 60 °C, pH 10.0), compared with only 3.4% for wild-type BacPelA. The combined mutant increased the weight loss of ramie fibers in degumming by 30.2% compared with wild-type BacPelA. This work provides a thermo-alkaline stable, highly active pectate lyase with great potential for application in the textile industry, and also illustrates an effective strategy for rational design and improvement of pectate lyases.
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Wang J, Liu Z, Pan X, Wang N, Li L, Du Y, Li J, Li M. Structural and Biochemical Analysis Reveals Catalytic Mechanism of Fucoidan Lyase from Flavobacterium sp. SA-0082. Mar Drugs 2022; 20:md20080533. [PMID: 36005536 PMCID: PMC9410043 DOI: 10.3390/md20080533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 11/24/2022] Open
Abstract
Fucoidans represent a type of polyanionic fucose-containing sulfated polysaccharides (FCSPs) that are cleaved by fucoidan-degrading enzymes, producing low-molecular-weight fucoidans with multiple biological activities suitable for pharmacological use. Most of the reported fucoidan-degrading enzymes are glycoside hydrolases, which have been well studied for their structures and catalytic mechanisms. Little is known, however, about the rarer fucoidan lyases, primarily due to the lack of structural information. FdlA from Flavobacterium sp. SA-0082 is an endo-type fucoidan-degrading enzyme that cleaves the sulfated fuco-glucuronomannan (SFGM) through a lytic mechanism. Here, we report nine crystal structures of the catalytic N-terminal domain of FdlA (FdlA-NTD), in both its wild type (WT) and mutant forms, at resolutions ranging from 1.30 to 2.25 Å. We show that the FdlA-NTD adopts a right-handed parallel β-helix fold, and possesses a substrate binding site composed of a long groove and a unique alkaline pocket. Our structural, biochemical, and enzymological analyses strongly suggest that FdlA-NTD utilizes catalytic residues different from other β-helix polysaccharide lyases, potentially representing a novel polysaccharide lyase family.
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Affiliation(s)
- Juanjuan Wang
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Zebin Liu
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
- College of Life Science, Capital Normal University, Beijing 100101, China
| | - Xiaowei Pan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- College of Life Science, Capital Normal University, Beijing 100101, China
| | - Ning Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Legong Li
- College of Life Science, Capital Normal University, Beijing 100101, China
| | - Yuguang Du
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Jianjun Li
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
- Correspondence: (J.L.); (M.L.)
| | - Mei Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- Correspondence: (J.L.); (M.L.)
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Xu H, Feng X, Yang Q, Zheng K, Yi L, Duan S, Cheng L. Improvement on Thermostability of Pectate Lyase and Its Potential Application to Ramie Degumming. Polymers (Basel) 2022; 14:polym14142878. [PMID: 35890653 PMCID: PMC9318251 DOI: 10.3390/polym14142878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 12/04/2022] Open
Abstract
In order to obtain a thermostable pectate lyase for ramie degumming, a rational design based on structural analysis was carried out on a novel pectate lyase (Pel419) derived from the Dickeya Dadantii DCE-01 for high-efficiency ramie degumming. A total of five potential amino acid sites were chosen to replace residues. Then, the mutant enzymes were subjected to the heterologous expressions in Escherichia coli and their enzymatic characteristics were determined. The optimal reaction temperature for the five mutants kept consistent with that for the wild type. The enzyme activity and thermal stability of mutant V52A were significantly improved. Meanwhile, the weight loss rate obtained by V52A with the best enzymatic characteristics in the ramie degumming process at 50 °C is comparable with that obtained by commercial cotton-ramie processing pectinases, indicating that V52A was a potential industrial enzyme that could be applied to large-scale ramie degumming. In this study, the biological functions of conservative residues of Pel419 were preliminarily explored. The mutant V52A with both enzymatic activity and improved heat resistance was acquired, providing a superior material for developing enzyme preparations of ramie degumming, and rendering an effective method for the rational design aiming to improve the thermostability of pectate lyase.
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Affiliation(s)
| | | | | | | | | | - Shengwen Duan
- Correspondence: (S.D.); (L.C.); Tel.: +86-0731-88998516 (L.C.)
| | - Lifeng Cheng
- Correspondence: (S.D.); (L.C.); Tel.: +86-0731-88998516 (L.C.)
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Chen Y, Li W, Turner JA, Anderson CT. PECTATE LYASE LIKE12 patterns the guard cell wall to coordinate turgor pressure and wall mechanics for proper stomatal function in Arabidopsis. THE PLANT CELL 2021; 33:3134-3150. [PMID: 34109391 PMCID: PMC8462824 DOI: 10.1093/plcell/koab161] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Indexed: 05/02/2023]
Abstract
Plant cell deformations are driven by cell pressurization and mechanical constraints imposed by the nanoscale architecture of the cell wall, but how these factors are controlled at the genetic and molecular levels to achieve different types of cell deformation is unclear. Here, we used stomatal guard cells to investigate the influences of wall mechanics and turgor pressure on cell deformation and demonstrate that the expression of the pectin-modifying gene PECTATE LYASE LIKE12 (PLL12) is required for normal stomatal dynamics in Arabidopsis thaliana. Using nanoindentation and finite element modeling to simultaneously measure wall modulus and turgor pressure, we found that both values undergo dynamic changes during induced stomatal opening and closure. PLL12 is required for guard cells to maintain normal wall modulus and turgor pressure during stomatal responses to light and to tune the levels of calcium crosslinked pectin in guard cell walls. Guard cell-specific knockdown of PLL12 caused defects in stomatal responses and reduced leaf growth, which were associated with lower cell proliferation but normal cell expansion. Together, these results force us to revise our view of how wall-modifying genes modulate wall mechanics and cell pressurization to accomplish the dynamic cellular deformations that underlie stomatal function and tissue growth in plants.
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Affiliation(s)
- Yintong Chen
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, 16802 USA
| | - Wenlong Li
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588 USA
| | - Joseph A. Turner
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588 USA
| | - Charles T. Anderson
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, 16802 USA
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Zheng L, Xu Y, Li Q, Zhu B. Pectinolytic lyases: a comprehensive review of sources, category, property, structure, and catalytic mechanism of pectate lyases and pectin lyases. BIORESOUR BIOPROCESS 2021; 8:79. [PMID: 38650254 PMCID: PMC10992409 DOI: 10.1186/s40643-021-00432-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 08/16/2021] [Indexed: 12/22/2022] Open
Abstract
Pectate lyases and pectin lyases have essential roles in various biotechnological applications, such as textile industry, paper making, pectic wastewater pretreatment, juice clarification and oil extraction. They can effectively cleave the α-1,4-glycosidic bond of pectin molecules back bone by β-elimination reaction to produce pectin oligosaccharides. In this way, it will not generate highly toxic methanol and has the advantages of good enzymatic selectivity, less by-products, mild reaction conditions and high efficiency. However, numerous researches have been done for several decades; there are still no comprehensive reviews to summarize the recent advances of pectate lyases and pectin lyases. This review tries to fill this gap by providing all relevant information, including the substrate, origin, biochemical properties, sequence analysis, mode of action, the three-dimensional structure and catalytic mechanism.
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Affiliation(s)
- Ling Zheng
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, P. R. China
| | - Yinxiao Xu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, P. R. China
| | - Qian Li
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, P. R. China
| | - Benwei Zhu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, P. R. China.
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Wu P, Yang S, Zhan Z, Zhang G. Origins and features of pectate lyases and their applications in industry. Appl Microbiol Biotechnol 2020; 104:7247-7260. [PMID: 32666183 DOI: 10.1007/s00253-020-10769-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 05/12/2020] [Accepted: 07/02/2020] [Indexed: 11/25/2022]
Abstract
Pectate lyase treatment can be an alternative strategy of the chemical processing, which causes severe environmental pollution, and has been broadly studied and applied for diverse industrial applications including textile industry, beverage industry, pulp processing, pectic wastewater pretreatment, and oil extraction. This review gave a brief description of the origins, enzymatic characterizations, structure, and applications of pectate lyases (Pels). Most of the reported pectate lyases are originated from microorganisms with a small number of them from plants and animals. Due to the diverse environments that these microorganisms exist, Pels present diversified features, especially for the range of optimal pH and temperature. The diversified biochemical properties of Pels define their applications in different industries, and the applications of alkaline Pels on cotton bioscouring and ramie degumming in textile industry were focused in this review. This review also discussed the perspectives of the development and applications of Pels. KEY POINTS: • The first review on pectate lyase focusing on biotechnological applications. • Origins, features, structures, applications of pectate lyases reviewed. • Applications of alkaline Pels in textile industry demonstrated. • Perspectives on future development and applications of Pels discussed.
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Affiliation(s)
- Pan Wu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, School of Life Sciences, Hubei University, Wuhan, 430062, China
- Wuhan Sunhy Biology Co., Ltd., Wuhan, 430206, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, School of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Zhichun Zhan
- Wuhan Sunhy Biology Co., Ltd., Wuhan, 430206, China
| | - Guimin Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, School of Life Sciences, Hubei University, Wuhan, 430062, China.
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15
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Kanungo A, Bag BP. Structural insights into the molecular mechanisms of pectinolytic enzymes. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/s42485-019-00027-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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16
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Nilo-Poyanco R, Vizoso P, Sanhueza D, Balic I, Meneses C, Orellana A, Campos-Vargas R. A Prunus persica genome-wide RNA-seq approach uncovers major differences in the transcriptome among chilling injury sensitive and non-sensitive varieties. PHYSIOLOGIA PLANTARUM 2019; 166:772-793. [PMID: 30203620 DOI: 10.1111/ppl.12831] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 08/28/2018] [Accepted: 09/03/2018] [Indexed: 05/14/2023]
Abstract
Chilling injury represents a major constrain for crops productivity. Prunus persica, one of the most relevant rosacea crops, have early season varieties that are resistant to chilling injury, in contrast to late season varieties, which display chilling symptoms such as mealiness (dry, sandy fruit mesocarp) after prolonged storage at chilling temperatures. To uncover the molecular processes related to the ability of early varieties to withstand mealiness, postharvest and genome-wide RNA-seq assessments were performed in two early and two late varieties. Differences in juice content and ethylene biosynthesis were detected among early and late season fruits that became mealy after exposed to prolonged chilling. Principal component and data distribution analysis revealed that cold-stored late variety fruit displayed an exacerbated and unique transcriptome profile when compared to any other postharvest condition. A differential expression analysis performed using an empirical Bayes mixture modeling approach followed by co-expression and functional enrichment analysis uncover processes related to ethylene, lipids, cell wall, carotenoids and DNA metabolism, light response, and plastid homeostasis associated to the susceptibility or resistance of P. persica varieties to chilling stress. Several of the genes related to these processes are in quantitative trait loci (QTL) associated to mealiness in P. persica. Together, these analyses exemplify how P. persica can be used as a model for studying chilling stress in plants.
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Affiliation(s)
- Ricardo Nilo-Poyanco
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Paula Vizoso
- Centro de Propagación y Conservación Vegetal, Universidad Mayor, Santiago, Chile
| | - Dayan Sanhueza
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Iván Balic
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- Departamento de Ciencias Biológicas, Universidad de Los Lagos, Osorno, Chile
| | - Claudio Meneses
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- FONDAP Center for Genome Regulation, Santiago, Chile
| | - Ariel Orellana
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- FONDAP Center for Genome Regulation, Santiago, Chile
| | - Reinaldo Campos-Vargas
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
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Luo X, Cao D, Zhang J, Chen L, Xia X, Li H, Zhao D, Zhang F, Xue H, Chen L, Li Y, Cao S. Integrated microRNA and mRNA expression profiling reveals a complex network regulating pomegranate (Punica granatum L.) seed hardness. Sci Rep 2018; 8:9292. [PMID: 29915181 PMCID: PMC6006261 DOI: 10.1038/s41598-018-27664-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 06/05/2018] [Indexed: 12/31/2022] Open
Abstract
The breeding of new soft-seeded pomegranate cultivars provides new products for the market and increases farmers' incomes, yet the genetic architecture mediating seed hardness is largely unknown. Here, the seed hardness and hundred-seed weights of 26 cultivars were determined in 2 successive years. We conducted miRNA and mRNA sequencing to analyse the seeds of two varieties of Punica granatum: soft-seeded Tunisia and hard-seeded Sanbai, at 60 and 120 d after flowering. Seed hardness was strongly positively correlated with hundred-seed weight. We detected 25 and 12 differentially expressed miRNA-mRNA pairs with negative regulatory relationships between the two genotypes at 60 and 120 d after flowering, respectively. These miRNA-mRNA pairs mainly regulated seed hardness by altering cell wall structure. Transcription factors including NAC1, WRKY and MYC, which are involved in seed hardness, were targeted by differentially expressed mdm-miR164e and mdm-miR172b. Thus, seed hardness is the result of a complex biological process regulated by a miRNA-mRNA network in pomegranate. These results will help us understand the complexity of seed hardness and help to elucidate the miRNA-mediated molecular mechanisms that contribute to seed hardness in pomegranate.
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Affiliation(s)
- Xiang Luo
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, P.R. China
| | - Da Cao
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, P.R. China
| | - Jianfeng Zhang
- Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, 450001, P.R. China
| | - Li Chen
- National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement in Wuhan, Huazhong Agricultural University, Wuhan, 430070, P.R. China
| | - Xiaocong Xia
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, P.R. China
| | - Haoxian Li
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, P.R. China
| | - Diguang Zhao
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, P.R. China
| | - Fuhong Zhang
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, P.R. China
| | - Hui Xue
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, P.R. China
| | - Lina Chen
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, P.R. China
| | - Yongzhou Li
- College of Horticultural Science, Henan Agricultural University, Zhengzhou, 450002, P.R. China
| | - Shangyin Cao
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, P.R. China.
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Periplasmic depolymerase provides insight into ABC transporter-dependent secretion of bacterial capsular polysaccharides. Proc Natl Acad Sci U S A 2018; 115:E4870-E4879. [PMID: 29735649 PMCID: PMC6003464 DOI: 10.1073/pnas.1801336115] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Capsules are critical virulence determinants for bacterial pathogens. They are composed of capsular polysaccharides (CPSs) with diverse structures, whose assembly on the cell surface is often powered by a conserved ABC transporter. Current capsule-assembly models include a contiguous trans-envelope channel directing nascent CPSs from the transporter to the cell surface. This conserved apparatus is an attractive target for antivirulence antimicrobial development. This work describes a CPS depolymerizing lyase enzyme found in the Burkholderiales and unique structural features that define its mechanism, CPS specificity, and evolution to function in the periplasm in a noncatabolic role. The activity of this enzyme provides evidence that CPS assembled in an ABC transporter-dependent system is exposed to periplasm during translocation to the cell surface. Capsules are surface layers of hydrated capsular polysaccharides (CPSs) produced by many bacteria. The human pathogen Salmonella enterica serovar Typhi produces “Vi antigen” CPS, which contributes to virulence. In a conserved strategy used by bacteria with diverse CPS structures, translocation of Vi antigen to the cell surface is driven by an ATP-binding cassette (ABC) transporter. These transporters are engaged in heterooligomeric complexes proposed to form an enclosed translocation conduit to the cell surface, allowing the transporter to power the entire process. We identified Vi antigen biosynthesis genetic loci in genera of the Burkholderiales, which are paradoxically distinguished from S. Typhi by encoding VexL, a predicted pectate lyase homolog. Biochemical analyses demonstrated that VexL is an unusual metal-independent endolyase with an acidic pH optimum that is specific for O-acetylated Vi antigen. A 1.22-Å crystal structure of the VexL-Vi antigen complex revealed features which distinguish common secreted catabolic pectate lyases from periplasmic VexL, which participates in cell-surface assembly. VexL possesses a right-handed parallel β-superhelix, of which one face forms an electropositive glycan-binding groove with an extensive hydrogen bonding network that includes Vi antigen acetyl groups and confers substrate specificity. VexL provided a probe to interrogate conserved features of the ABC transporter-dependent export model. When introduced into S. Typhi, VexL localized to the periplasm and degraded Vi antigen. In contrast, a cytosolic derivative had no effect unless export was disrupted. These data provide evidence that CPS assembled in ABC transporter-dependent systems is actually exposed to the periplasm during envelope translocation.
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Yamaguchi Y, Yamamoto H, Tobisawa Y, Irie F. TMEM2: A missing link in hyaluronan catabolism identified? Matrix Biol 2018; 78-79:139-146. [PMID: 29601864 DOI: 10.1016/j.matbio.2018.03.020] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/17/2018] [Accepted: 03/25/2018] [Indexed: 12/20/2022]
Abstract
Hyaluronan (HA) is a glycosaminoglycan (GAG) composed of repeating disaccharide units of glucuronic acid and N-acetylglucosamine. HA is an extremely long, unbranched polymer, which often exceeds 106 Da and sometimes reaches 107 Da. A feature that epitomizes HA is its rapid turnover; one-third of the total body HA is turned over daily. The current model of HA catabolism postulates that high-molecular weight HA in the extracellular space is first cleaved into smaller fragments by a hyaluronidase(s) that resides at the cell surface, followed by internalization of fragments and their degradation into monosaccharides in lysosomes. Over the last decade, considerable research has shown that the HYAL family of hyaluronidases plays significant roles in HA catabolism. Nonetheless, the identity of a hyaluronidase responsible for the initial step of HA cleavage on the cell surface remains elusive, as biochemical and enzymological properties of HYAL proteins are not entirely consistent with those expected of cell surface hyaluronidases. Recent identification of transmembrane 2 (TMEM2) as a cell surface protein that possesses potent hyaluronidase activity suggests that it may be the "missing" cell surface hyaluronidase, and that novel models of HA catabolism should include this protein.
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Affiliation(s)
- Yu Yamaguchi
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Hayato Yamamoto
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Yuki Tobisawa
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Fumitoshi Irie
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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Structural basis for the role of serine-rich repeat proteins from Lactobacillus reuteri in gut microbe-host interactions. Proc Natl Acad Sci U S A 2018; 115:E2706-E2715. [PMID: 29507249 PMCID: PMC5866549 DOI: 10.1073/pnas.1715016115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Gut bacteria play a key role in health and disease, but the molecular mechanisms underpinning their interaction with the host remain elusive. The serine-rich repeat proteins (SRRPs) are a family of adhesins identified in many Gram-positive pathogenic bacteria. We previously showed that beneficial bacterial species found in the gut also express SRRPs and that SRRP was required for the ability of Lactobacillus reuteri strain to colonize mice. Here, our structural and biochemical data reveal that L. reuteri SRRP adopts a β-solenoid fold not observed in other structurally characterized SRRPs and functions as an adhesin via a pH-dependent mechanism, providing structural insights into the role of these adhesins in biofilm formation of gut symbionts. Lactobacillus reuteri, a Gram-positive bacterial species inhabiting the gastrointestinal tract of vertebrates, displays remarkable host adaptation. Previous mutational analyses of rodent strain L. reuteri 100-23C identified a gene encoding a predicted surface-exposed serine-rich repeat protein (SRRP100-23) that was vital for L. reuteri biofilm formation in mice. SRRPs have emerged as an important group of surface proteins on many pathogens, but no structural information is available in commensal bacteria. Here we report the 2.00-Å and 1.92-Å crystal structures of the binding regions (BRs) of SRRP100-23 and SRRP53608 from L. reuteri ATCC 53608, revealing a unique β-solenoid fold in this important adhesin family. SRRP53608-BR bound to host epithelial cells and DNA at neutral pH and recognized polygalacturonic acid (PGA), rhamnogalacturonan I, or chondroitin sulfate A at acidic pH. Mutagenesis confirmed the role of the BR putative binding site in the interaction of SRRP53608-BR with PGA. Long molecular dynamics simulations showed that SRRP53608-BR undergoes a pH-dependent conformational change. Together, these findings provide mechanistic insights into the role of SRRPs in host–microbe interactions and open avenues of research into the use of biofilm-forming probiotics against clinically important pathogens.
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Yamamoto H, Tobisawa Y, Inubushi T, Irie F, Ohyama C, Yamaguchi Y. A mammalian homolog of the zebrafish transmembrane protein 2 (TMEM2) is the long-sought-after cell-surface hyaluronidase. J Biol Chem 2017; 292:7304-7313. [PMID: 28246172 DOI: 10.1074/jbc.m116.770149] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Revised: 02/27/2017] [Indexed: 12/31/2022] Open
Abstract
Hyaluronan (HA) is an extremely large polysaccharide (glycosaminoglycan) involved in many cellular functions. HA catabolism is thought to involve the initial cleavage of extracellular high-molecular-weight (HMW) HA into intermediate-size HA by an extracellular or cell-surface hyaluronidase, internalization of intermediate-size HA, and complete degradation into monosaccharides in lysosomes. Despite considerable research, the identity of the hyaluronidase responsible for the initial HA cleavage in the extracellular space remains elusive. HYAL1 and HYAL2 have properties more consistent with lysosomal hyaluronidases, whereas CEMIP/KIAA1199, a recently identified HA-binding molecule that has HA-degrading activity, requires the participation of the clathrin-coated pit pathway of live cells for HA degradation. Here we show that transmembrane protein 2 (TMEM2), a mammalian homolog of a protein playing a role in zebrafish endocardial cushion development, is a cell-surface hyaluronidase. Live immunostaining and surface biotinylation assays confirmed that mouse TMEM2 is expressed on the cell surface in a type II transmembrane topology. TMEM2 degraded HMW-HA into ∼5-kDa fragments but did not cleave chondroitin sulfate or dermatan sulfate, indicating its specificity to HA. The hyaluronidase activity of TMEM2 was Ca2+-dependent; the enzyme's pH optimum is around 6-7, and unlike CEMIP/KIAA1199, TMEM2 does not require the participation of live cells for its hyaluronidase activity. Moreover, TMEM2-expressing cells could eliminate HA immobilized on a glass surface in a contact-dependent manner. Together, these data suggest that TMEM2 is the long-sought-after hyaluronidase that cleaves extracellular HMW-HA into intermediate-size fragments before internalization and degradation in the lysosome.
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Affiliation(s)
- Hayato Yamamoto
- From the Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037 and
| | - Yuki Tobisawa
- From the Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037 and
| | - Toshihiro Inubushi
- From the Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037 and
| | - Fumitoshi Irie
- From the Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037 and
| | - Chikara Ohyama
- the Department of Urology, Hirosaki University Graduate School of Medicine, Hirosaki 036-8562, Japan
| | - Yu Yamaguchi
- From the Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037 and
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22
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Zhou Z, Liu Y, Chang Z, Wang H, Leier A, Marquez-Lago TT, Ma Y, Li J, Song J. Structure-based engineering of a pectate lyase with improved specific activity for ramie degumming. Appl Microbiol Biotechnol 2016; 101:2919-2929. [PMID: 28028551 DOI: 10.1007/s00253-016-7994-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 10/26/2016] [Accepted: 11/05/2016] [Indexed: 11/27/2022]
Abstract
Biotechnological applications of microbial pectate lyases (Pels) in plant fiber processing are promising, eco-friendly substitutes for conventional chemical degumming processes. However, to potentiate the enzymes' use for industrial applications, resolving the molecular structure to elucidate catalytic mechanisms becomes necessary. In this manuscript, we report the high resolution (1.45 Å) crystal structure of pectate lyase (pelN) from Paenibacillus sp. 0602 in apo form. Through sequence alignment and structural superposition with other members of the polysaccharide lyase (PL) family 1 (PL1), we determined that pelN shares the characteristic right-handed β-helix and is structurally similar to other members of the PL1 family, while exhibiting key differences in terms of catalytic and substrate binding residues. Then, based on information from structure alignments with other PLs, we engineered a novel pelN. Our rational design yielded a pelN mutant with a temperature for enzymatic activity optimally shifted from 67.5 to 60 °C. Most importantly, this pelN mutant displayed both higher specific activity and ramie fiber degumming ability when compared with the wild-type enzyme. Altogether, our rational design method shows great potential for industrial applications. Moreover, we expect the reported high-resolution crystal structure to provide a solid foundation for future rational, structure-based engineering of genetically enhanced pelNs.
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Affiliation(s)
- Zhanping Zhou
- National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Yang Liu
- National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Zhenying Chang
- National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Huilin Wang
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - André Leier
- Isaac Newton Institute for Mathematical Sciences, University of Cambridge, Cambridge, UK
| | - Tatiana T Marquez-Lago
- Isaac Newton Institute for Mathematical Sciences, University of Cambridge, Cambridge, UK
| | - Yanhe Ma
- National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Jian Li
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, VIC, 3800, Australia
| | - Jiangning Song
- National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, 3800, Australia.
- Monash Centre for Data Science, Faculty of Information Technology, Monash University, Melbourne, VIC, 3800, Australia.
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23
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Ali S, Søndergaard CR, Teixeira S, Pickersgill RW. Structural insights into the loss of catalytic competence in pectate lyase activity at low pH. FEBS Lett 2015; 589:3242-6. [PMID: 26420545 DOI: 10.1016/j.febslet.2015.09.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 09/20/2015] [Indexed: 10/23/2022]
Abstract
Pectate lyase, a family 1 polysaccharide lyase, catalyses cleavage of the α-1,4 linkage of the polysaccharide homogalacturonan via an anti β-elimination reaction. In the Michaelis complex two calcium ions bind between the C6 carboxylate of the d-galacturonate residue and enzyme aspartates at the active centre (+1 subsite), they withdraw electrons acidifying the C5 proton facilitating its abstraction by the catalytic arginine. Here we show that activity is lost at low pH because protonation of aspartates results in the loss of the two catalytic calcium-ions causing a profound failure to correctly organise the Michaelis complex.
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Affiliation(s)
- Salyha Ali
- Institut Laue Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France; School of Biological and Chemical Sciences, Queen Mary University of London, Department of Chemistry & Biochemistry, Mile End Road, London E1 4NS, United Kingdom
| | | | - Susana Teixeira
- Institut Laue Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France; EPSAM, Keele University, Staffordshire ST5 5BG, United Kingdom
| | - Richard W Pickersgill
- School of Biological and Chemical Sciences, Queen Mary University of London, Department of Chemistry & Biochemistry, Mile End Road, London E1 4NS, United Kingdom.
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24
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Alahuhta M, Taylor LE, Brunecky R, Sammond DW, Michener W, Adams MWW, Himmel ME, Bomble YJ, Lunin V. The catalytic mechanism and unique low pH optimum of Caldicellulosiruptor bescii family 3 pectate lyase. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:1946-54. [PMID: 26327384 PMCID: PMC4556314 DOI: 10.1107/s1399004715013760] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 07/20/2015] [Indexed: 11/10/2022]
Abstract
The unique active site of the Caldicellulosiruptor bescii family 3 pectate lyase (PL3) enzyme has been thoroughly characterized using a series of point mutations, X-ray crystallography, pK(a) calculations and biochemical assays. The X-ray structures of seven PL3 active-site mutants, five of them in complex with intact trigalacturonic acid, were solved and characterized structurally, biochemically and computationally. The results confirmed that Lys108 is the catalytic base, but there is no clear candidate for the catalytic acid. However, the reaction mechanism can also be explained by an antiperiplanar trans-elimination reaction, in which Lys108 abstracts a proton from the C5 atom without the help of simultaneous proton donation by an acidic residue. An acidified water molecule completes the anti β-elimination reaction by protonating the O4 atom of the substrate. Both the C5 hydrogen and C4 hydroxyl groups of the substrate must be orientated in axial configurations, as for galacturonic acid, for this to be possible. The wild-type C. bescii PL3 displays a pH optimum that is lower than that of Bacillus subtilis PL1 according to activity measurements, indicating that C. bescii PL3 has acquired a lower pH optimum by utilizing lysine instead of arginine as the catalytic base, as well as by lowering the pK(a) of the catalytic base in a unique active-site environment.
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Affiliation(s)
- Markus Alahuhta
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Larry E. Taylor
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Roman Brunecky
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Deanne W. Sammond
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - William Michener
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Michael W. W. Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602-7229, USA
| | - Michael E. Himmel
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Yannick J. Bomble
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Vladimir Lunin
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
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25
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Directed Evolution and Structural Analysis of Alkaline Pectate Lyase from the Alkaliphilic Bacterium Bacillus sp. Strain N16-5 To Improve Its Thermostability for Efficient Ramie Degumming. Appl Environ Microbiol 2015; 81:5714-23. [PMID: 26070675 DOI: 10.1128/aem.01017-15] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 06/07/2015] [Indexed: 11/20/2022] Open
Abstract
Thermostable alkaline pectate lyases have potential applications in the textile industry as an alternative to chemical-based ramie degumming processes. In particular, the alkaline pectate lyase from Bacillus sp. strain N16-5 (BspPelA) has potential for enzymatic ramie degumming because of its high specific activity under extremely alkaline conditions without the requirement for additional Ca(2+). However, BspPelA displays poor thermostability and is inactive after incubation at 50°C for only 30 min. Here, directed evolution was used to improve the thermostability of BspPelA for efficient and stable degumming. After two rounds of error-prone PCR and screening of >12,000 mutants, 10 mutants with improved thermostability were obtained. Sequence analysis and site-directed mutagenesis revealed that single E124I, T178A, and S271G substitutions were responsible for improving thermostability. Structural and molecular dynamic simulation analysis indicated that the formation of a hydrophobic cluster and new H-bond networks was the key factor contributing to the improvement in thermostability with these three substitutions. The most thermostable combined mutant, EAET, exhibited a 140-fold increase in the t50 (time at which the enzyme loses 50% of its initial activity) value at 50°C, accompanied by an 84.3% decrease in activity compared with that of wild-type BspPelA, while the most advantageous combined mutant, EA, exhibited a 24-fold increase in the t50 value at 50°C, with a 23.3% increase in activity. Ramie degumming with the EA mutant was more efficient than that with wild-type BspPelA. Collectively, our results suggest that the EA mutant, exhibiting remarkable improvements in thermostability and activity, has the potential for applications in ramie degumming in the textile industry.
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26
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Zhou XX, Yang LT, Qi YP, Guo P, Chen LS. Mechanisms on boron-induced alleviation of aluminum-toxicity in Citrus grandis seedlings at a transcriptional level revealed by cDNA-AFLP analysis. PLoS One 2015; 10:e0115485. [PMID: 25747450 PMCID: PMC4352013 DOI: 10.1371/journal.pone.0115485] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 11/24/2014] [Indexed: 11/18/2022] Open
Abstract
The physiological and biochemical mechanisms on boron (B)-induced alleviation of aluminum (B)-toxicity in plants have been examined in some details, but our understanding of the molecular mechanisms underlying these processes is very limited. In this study, we first used the cDNA-AFLP to investigate the gene expression patterns in Citrus grandis roots responsive to B and Al interactions, and isolated 100 differentially expressed genes. Results showed that genes related to detoxification of reactive oxygen species (ROS) and aldehydes (i.e., glutathione S-transferase zeta class-like isoform X1, thioredoxin M-type 4, and 2-alkenal reductase (NADP+-dependent)-like), metabolism (i.e., carboxylesterases and lecithin-cholesterol acyltransferase-like 4-like, nicotianamine aminotransferase A-like isoform X3, thiosulfate sulfurtransferase 18-like isoform X1, and FNR, root isozyme 2), cell transport (i.e., non-specific lipid-transfer protein-like protein At2g13820-like and major facilitator superfamily protein), Ca signal and hormone (i.e., calcium-binding protein CML19-like and IAA-amino acid hydrolase ILR1-like 4-like), gene regulation (i.e., Gag-pol polyprotein) and cell wall modification (i.e., glycosyl hydrolase family 10 protein) might play a role in B-induced alleviation of Al-toxicity. Our results are useful not only for our understanding of molecular processes associated with B-induced alleviation of Al-toxicity, but also for obtaining key molecular genes to enhance Al-tolerance of plants in the future.
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Affiliation(s)
- Xin-Xing Zhou
- College of Resource and Environmental Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Horticultural Plant Physiology, Biochemistry and Molecular Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lin-Tong Yang
- College of Resource and Environmental Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Horticultural Plant Physiology, Biochemistry and Molecular Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yi-Ping Qi
- Institute of Materia Medica, Fujian Academy of Medical Sciences, Fuzhou 350001, China
| | - Peng Guo
- College of Resource and Environmental Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Horticultural Plant Physiology, Biochemistry and Molecular Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Li-Song Chen
- College of Resource and Environmental Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Horticultural Plant Physiology, Biochemistry and Molecular Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- The Higher Educational Key Laboratory of Fujian Province for Soil Ecosystem Health and Regulation, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Fujian Key Laboratory for Plant Molecular and Cell Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- * E-mail:
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27
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Chakraborty S, Fernandes VO, Dias FMV, Prates JAM, Ferreira LMA, Fontes CMGA, Goyal A, Centeno MSJ. Role of pectinolytic enzymes identified in Clostridium thermocellum cellulosome. PLoS One 2015; 10:e0116787. [PMID: 25658912 PMCID: PMC4319962 DOI: 10.1371/journal.pone.0116787] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 12/09/2014] [Indexed: 11/30/2022] Open
Abstract
The cloning, expression and characterization of three cellulosomal pectinolytic enzymes viz., two variants of PL1 (PL1A and PL1B) and PL9 from Clostridium thermocellum was carried out. The comparison of the primary sequences of PL1A, PL1B and PL9 revealed that these proteins displayed considerable sequence similarities with family 1 and 9 polysaccharide lyases, respectively. PL1A, PL1B and PL9 are the putative catalytic domains of protein sequence ABN54148.1 and ABN53381.1 respectively. These two protein sequences also contain putative carbohydrate binding module (CBM) and type-I dockerin. The associated putative CBM of PL1A showed strong homology with family 6 CBMs while those of PL1B and PL9 showed homology with family 35 CBMs. Recombinant derivatives of these three enzymes showed molecular masses of approximately 34 kDa, 40 kDa and 32 kDa for PL1A, PL1B and PL9, respectively. PL1A, PL1B and PL9 displayed high activity toward polygalacturonic acid and pectin (up to 55% methyl-esterified) from citrus fruits. However, PL1B showed relatively higher activity towards 55% and 85% methyl-esterified pectin (citrus). PL1A and PL9 showed higher activity on rhamnogalacturonan than PL1B. Both PL1A and PL9 displayed maximum activity at pH 8.5 with optimum temperature of 50°C and 60°C respectively. PL1B achieved highest activity at pH 9.8, under an optimum temperature of 50°C. PL1A, PL1B and PL9 all produced two or more unsaturated galacturonates from pectic substrates as displayed by TLC analysis confirming that they are endo-pectate lyase belonging to family 1 and 9, respectively. This report reveals that pectinolytic activity displayed by Clostridium thermocellum cellulosome is coordinated by a sub-set of at least three multi-modular enzymes.
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Affiliation(s)
- Soumyadeep Chakraborty
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Vania O. Fernandes
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Fernando M. V. Dias
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Jose A. M. Prates
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Luis M. A. Ferreira
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | | | - Arun Goyal
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
- * E-mail: (AG); (MSJC)
| | - Maria S. J. Centeno
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
- * E-mail: (AG); (MSJC)
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Hugouvieux-Cotte-Pattat N, Condemine G, Shevchik VE. Bacterial pectate lyases, structural and functional diversity. ENVIRONMENTAL MICROBIOLOGY REPORTS 2014; 6:427-40. [PMID: 25646533 DOI: 10.1111/1758-2229.12166] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Pectate lyases are enzymes involved in plant cell wall degradation. They cleave pectin using a β-elimination mechanism, specific for acidic polysaccharides. They are mainly produced by plant pathogens and plant-associated organisms, and only rarely by animals. Pectate lyases are also commonly produced in the bacterial world, either by bacteria living in close proximity with plants or by gut bacteria that find plant material in the digestive tract of their hosts. The role of pectate lyases is essential for plant pathogens, such as Dickeya dadantii, that use a set of pectate lyases as their main virulence factor. Symbiotic bacteria produce their own pectate lyases, but they also induce plant pectate lyases to initiate the symbiosis. Pectin degradation products may act as signals affecting the plant–bacteria interactions. Bacterial pectate lyases are also essential for using the pectin of dead or living plants as a carbon source for growth. In the animal gut, Bacteroides pectate lyases degrade the pectin of ingested food, and this is particularly important for herbivores that depend on their microflora for the digestion of pectin. Some human pathogens, such as Yersinia enterocolitica, produce a few intracellular pectate lyases that can facilitate their growth in the presence of highly pectinolytic bacteria, at the plant surface, in the soil or in the animal gut.
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29
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Wang MH, Kim JG, Ahn SE, Lee AY, Bae TM, Kim DR, Hwang YS. Potential role of pectate lyase and Ca(2+) in the increase in strawberry fruit firmness induced by short-term treatment with high-pressure CO2. J Food Sci 2014; 79:S685-92. [PMID: 24592970 DOI: 10.1111/1750-3841.12382] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 01/09/2014] [Indexed: 11/30/2022]
Abstract
Postharvest treatment with high-pressure CO2 helps to control decay and increase firmness in strawberries. Increases in firmness occurred through modification of calcium binding to cell wall. However, the mechanism(s) involved in Ca(2+) migration to pectic polymers and other physiological events associated with the maintenance of increased firmness are not clearly understood. The focus of this study was to find potential mechanism(s) that are associated with calcium movement, increases in firmness, or maintenance of firmness in strawberry fruit after high-pressure CO2 treatment. An increase in firmness was induced by high-pressure CO2 treatment, but not by high-pressure N2 treatment. This indicates that CO2 stimulates a change in firmness. The increase in firmness induced by high-pressure CO2 seems to involve calcium efflux. Using membrane Ca(2+) -dependent ATPase inhibitors sodium vanadate (250 μM) and erythrosin B (100 μM) delayed both the increase in firmness and calcium binding to wall polymers. Exogenous application of CaCl2 (10 mM) enhanced the firmness increase of fruit slices only when they were exposed to high-pressure CO2 . The activity of pectate lyase was downregulated by CO2 treatment, but β-galactosidase activity was not affected. The increase in strawberry firmness induced by high-pressure CO2 treatment primarily involves the efflux of calcium ions and their binding to wall polymers. These physiological changes are not induced by an anaerobic environment. The downregulation of wall-modifying enzymes, such as pectate lyase, appeared to contribute to the maintenance of firmness that was induced by high-pressure CO2 treatment.
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Affiliation(s)
- Mao Hua Wang
- Dept. of Horticultural Science, College of Agriculture and Life Science, Chungnam Natl. Univ., Deajeon, 305-764, South Korea
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30
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Hung JE, Fogle EJ, Garg N, Chekan JR, Nair SK, van der Donk WA. Chemical rescue and inhibition studies to determine the role of Arg301 in phosphite dehydrogenase. PLoS One 2014; 9:e87134. [PMID: 24498026 PMCID: PMC3909101 DOI: 10.1371/journal.pone.0087134] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 12/19/2013] [Indexed: 12/11/2022] Open
Abstract
Phosphite dehydrogenase (PTDH) catalyzes the NAD(+)-dependent oxidation of phosphite to phosphate. This reaction requires the deprotonation of a water nucleophile for attack on phosphite. A crystal structure was recently solved that identified Arg301 as a potential base given its proximity and orientation to the substrates and a water molecule within the active site. Mutants of this residue showed its importance for efficient catalysis, with about a 100-fold loss in k cat and substantially increased K m,phosphite for the Ala mutant (R301A). The 2.35 Å resolution crystal structure of the R301A mutant with NAD(+) bound shows that removal of the guanidine group renders the active site solvent exposed, suggesting the possibility of chemical rescue of activity. We show that the catalytic activity of this mutant is restored to near wild-type levels by the addition of exogenous guanidinium analogues; Brønsted analysis of the rates of chemical rescue suggests that protonation of the rescue reagent is complete in the transition state of the rate-limiting step. Kinetic isotope effects on the reaction in the presence of rescue agents show that hydride transfer remains at least partially rate-limiting, and inhibition experiments show that K i of sulfite with R301A is ∼400-fold increased compared to the parent enzyme, similar to the increase in K m for phosphite in this mutant. The results of our experiments indicate that Arg301 plays an important role in phosphite binding as well as catalysis, but that it is not likely to act as an active site base.
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Affiliation(s)
- John E. Hung
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Emily J. Fogle
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Neha Garg
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Jonathan R. Chekan
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Wilfred A. van der Donk
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
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Abstract
Over the sixty years since Koshland initially formulated the classical mechanisms for retaining and inverting glycosidases, researchers have assembled a large body of supporting evidence and have documented variations of these mechanisms. Recently, however, researchers have uncovered a number of completely distinct mechanisms for enzymatic cleavage of glycosides involving elimination and/or hydration steps. In family GH4 and GH109 glycosidases, the reaction proceeds via transient NAD(+)-mediated oxidation at C3, thereby acidifying the proton at C2 and allowing for elimination across the C1-C2 bond. Subsequent Michael-type addition of water followed by reduction at C3 generates the hydrolyzed product. Enzymes employing this mechanism can hydrolyze thioglycosides as well as both anomers of activated substrates. Sialidases employ a conventional retaining mechanism in which a tyrosine functions as the nucleophile, but in some cases researchers have observed off-path elimination end products. These reactions occur via the normal covalent intermediate, but instead of an attack by water on the anomeric center, the catalytic acid/base residue abstracts an adjacent proton. These enzymes can also catalyze hydration of the enol ether via the reverse pathway. Reactions of α-(1,4)-glucan lyases also proceed through a covalent intermediate with subsequent abstraction of an adjacent proton to give elimination. However, in this case, the departing carboxylate "nucleophile" serves as the base in a concerted but asynchronous syn-elimination process. These enzymes perform only elimination reactions. Polysaccharide lyases, which act on uronic acid-containing substrates, also catalyze only elimination reactions. Substrate binding neutralizes the charge on the carboxylate, which allows for abstraction of the proton on C5 and leads to an elimination reaction via an E1cb mechanism. These enzymes can also cleave thioglycosides, albeit slowly. The unsaturated product of polysaccharide lyases can then serve as a substrate for a hydration reaction carried out by unsaturated glucuronyl hydrolases. This hydration is initiated by protonation at C4 and proceeds in a Markovnikov fashion rather than undergoing a Michael-type addition, giving a hemiketal at C5. This hemiketal then undergoes a rearrangement that results in cleavage of the anomeric bond. These enzymes can also hydrolyze thioglycosides efficiently and slowly turn over substrates with inverted anomeric configuration. The mechanisms discussed in this Account proceed through transition states that involve either positive or negative charges, unlike the exclusively cationic transition states of the classical Koshland retaining and inverting glycosidases. In addition, the distribution of this charge throughout the substrate can vary substantially. The nature of these mechanisms and their transition states means that any inhibitors or inactivators of these unusual enzymes probably differ from those presently used for Koshland retaining or inverting glycosidases.
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Affiliation(s)
- Seino A. K. Jongkees
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Stephen G. Withers
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
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32
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Wolfram F, Kitova EN, Robinson H, Walvoort MTC, Codée JDC, Klassen JS, Howell PL. Catalytic mechanism and mode of action of the periplasmic alginate epimerase AlgG. J Biol Chem 2014; 289:6006-19. [PMID: 24398681 DOI: 10.1074/jbc.m113.533158] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that forms chronic biofilm infections in the lungs of cystic fibrosis patients. A major component of the biofilm during these infections is the exopolysaccharide alginate, which is synthesized at the inner membrane as a homopolymer of 1-4-linked β-D-mannuronate. As the polymer passages through the periplasm, 22-44% of the mannuronate residues are converted to α-L-guluronate by the C5-epimerase AlgG to produce a polymer of alternating β-D-mannuronate and α-L-guluronate blocks and stretches of polymannuronate. To understand the molecular basis of alginate epimerization, the structure of Pseudomonas syringae AlgG has been determined at 2.1-Å resolution, and the protein was functionally characterized. The structure reveals that AlgG is a long right-handed parallel β-helix with an elaborate lid structure. Functional analysis of AlgG mutants suggests that His(319) acts as the catalytic base and that Arg(345) neutralizes the acidic group during the epimerase reaction. Water is the likely catalytic acid. Electrostatic surface potential and residue conservation analyses in conjunction with activity and substrate docking studies suggest that a conserved electropositive groove facilitates polymannuronate binding and contains at least nine substrate binding subsites. These subsites likely align the polymer in the correct register for catalysis to occur. The presence of multiple subsites, the electropositive groove, and the non-random distribution of guluronate in the alginate polymer suggest that AlgG is a processive enzyme. Moreover, comparison of AlgG and the extracellular alginate epimerase AlgE4 of Azotobacter vinelandii provides a structural rationale for the differences in their Ca(2+) dependence.
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Affiliation(s)
- Francis Wolfram
- From the Program in Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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33
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Rozeboom HJ, Beldman G, Schols HA, Dijkstra BW. Crystal structure of endo-xylogalacturonan hydrolase fromAspergillus tubingensis. FEBS J 2013; 280:6061-9. [DOI: 10.1111/febs.12524] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 09/10/2013] [Indexed: 11/26/2022]
Affiliation(s)
- Henriëtte J. Rozeboom
- Laboratory of Biophysical Chemistry; Groningen Biomolecular Sciences and Biotechnology Institute; University of Groningen; The Netherlands
| | - Gerrit Beldman
- Laboratory of Food Chemistry; Wageningen University; The Netherlands
| | - Henk A. Schols
- Laboratory of Food Chemistry; Wageningen University; The Netherlands
| | - Bauke W. Dijkstra
- Laboratory of Biophysical Chemistry; Groningen Biomolecular Sciences and Biotechnology Institute; University of Groningen; The Netherlands
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34
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Thomas F, Lundqvist LCE, Jam M, Jeudy A, Barbeyron T, Sandström C, Michel G, Czjzek M. Comparative characterization of two marine alginate lyases from Zobellia galactanivorans reveals distinct modes of action and exquisite adaptation to their natural substrate. J Biol Chem 2013; 288:23021-37. [PMID: 23782694 DOI: 10.1074/jbc.m113.467217] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cell walls of brown algae are complex supramolecular assemblies containing various original, sulfated, and carboxylated polysaccharides. Among these, the major marine polysaccharide component, alginate, represents an important biomass that is successfully turned over by the heterotrophic marine bacteria. In the marine flavobacterium Zobellia galactanivorans, the catabolism and uptake of alginate are encoded by operon structures that resemble the typical Bacteroidetes polysaccharide utilization locus. The genome of Z. galactanivorans contains seven putative alginate lyase genes, five of which are localized within two clusters comprising additional carbohydrate-related genes. This study reports on the detailed biochemical and structural characterization of two of these. We demonstrate here that AlyA1PL7 is an endolytic guluronate lyase, and AlyA5 cleaves unsaturated units, α-L-guluronate or β-D-manuronate residues, at the nonreducing end of oligo-alginates in an exolytic fashion. Despite a common jelly roll-fold, these striking differences of the mode of action are explained by a distinct active site topology, an open cleft in AlyA1(PL7), whereas AlyA5 displays a pocket topology due to the presence of additional loops partially obstructing the catalytic groove. Finally, in contrast to PL7 alginate lyases from terrestrial bacteria, both enzymes proceed according to a calcium-dependent mechanism suggesting an exquisite adaptation to their natural substrate in the context of brown algal cell walls.
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Affiliation(s)
- François Thomas
- University of Marie and Pierre Curie Paris 6, UMR 7139, Marine Plants and Biomolecules, Station Biologique de Roscoff, F-29682 Roscoff, Brittany, France
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35
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Tang Q, Liu YP, Ren ZG, Yan XX, Zhang LQ. 1.37 Å crystal structure of pathogenic factor pectate lyase from Acidovorax citrulli. Proteins 2013; 81:1485-90. [PMID: 23568384 DOI: 10.1002/prot.24298] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 03/18/2013] [Accepted: 03/22/2013] [Indexed: 11/11/2022]
Abstract
Pectates lyase (Pel) plays an important role in bacteria pathogenicity. The crystal structure of Pel from Acidovorax citrulli (AcPel) has been solved to 1.37 Å resolution. AcPel belongs to the polysaccharide lyase family 1 (PL1), which has a characteristic right-handed β-helix fold. AcPel is similar with other Pels in the PL1 family, but also shows some differences at the substrate binding site.
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Affiliation(s)
- Qun Tang
- Department of Plant Pathology, China Agricultural University, Beijing, China
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36
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Abstract
Interactions among β-sheets occur widely in protein quaternary structure, protein-protein interaction, and protein aggregation and are central in Alzheimer's and other amyloid-related diseases. This Perspective looks at the structural biology of these important yet under-appreciated interactions from a supramolecular chemist's point of view. Common themes in the supramolecular interactions of β-sheets are identified and richly illustrated though examples from proteins, amyloids, and chemical model systems. β-Sheets interact through edge-to-edge hydrogen bonding to form extended layers and through face-to-face hydrophobic or van der Waals interactions to form layered sandwich-like structures. Side chains from adjacent layers can fit together through simple hydrophobic contacts or can participate in complementary interdigitation or knob-hole interactions. The layers can be aligned, offset, or rotated. The right-handed twist of β-sheets provides additional opportunities for stabilization of edge-to-edge contacts and rotated layered structures.
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Affiliation(s)
- Pin-Nan Cheng
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, USA
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37
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Alahuhta M, Brunecky R, Chandrayan P, Kataeva I, Adams MWW, Himmel ME, Lunin VV. The structure and mode of action of Caldicellulosiruptor bescii family 3 pectate lyase in biomass deconstruction. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:534-9. [PMID: 23519661 DOI: 10.1107/s0907444912050512] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 12/11/2012] [Indexed: 11/10/2022]
Abstract
The unique active site of the Caldicellulosiruptor bescii family 3 pectate lyase catalytic module (PL3-cat) has been structurally described and synergistic digestion studies with C. bescii cellulase A have been performed on unpretreated biomass. The X-ray structure of PL3-cat was determined at 1.6 Å resolution (PDB entry 4ew9) in complex with the products of trigalacturonic acid. Comparison with family 1 pectate lyase (PL1) structures shows that the active site of the PL3 catalytic module is considerably different. However, on superimposing the identical sugar rings at the -2 subsites conserved interactions could be identified. Interestingly, only one catalytic residue, the lysine that donates the proton to the carboxylate group in the β-elimination reaction of PL1 (Lys108 in PL3-cat), is conserved in PL3 and there is no arginine to abstract the proton from the C5 carbon of the galactouronate ring. This suggests that the reaction mechanism of PL3 requires different catalytic residues. Most interestingly, comparison with other proton-abstraction reactions reveals that in PL3 the α-proton is abstracted by a lysine, in a striking similarity to enolases. These observations led us to propose that in PL3-cat Lys108 is the catalytic base, Glu84 is the catalytic acid and an acidified water molecule completes the anti β-elimination reaction by protonating the O4 atom of the substrate. Also, our digestion experiments with unpretreated switchgrass show that the loadings of C. bescii cellobiohydrolase A (CelA) can be lowered by the addition of PL3 to the reaction mixture. This result suggests that PL3 can significantly improve the deconstruction of unpretreated biomass by allowing other enzymes to better access their preferred substrates.
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Affiliation(s)
- Markus Alahuhta
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401-3305, USA
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38
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Abstract
A macromolecular structure, as measured data or as a list of coordinates or even on-screen as a full atomic model, is an extremely complex and confusing object. The underlying rules of how it folds, moves, and interacts as a biological entity are even less evident or intuitive to the human mind. To do science on such molecules, or to relate them usefully to higher levels of biology, we need to start with a natural history that names their features in meaningful ways and with multiple representations (visual or algebraic) that show some aspect of their organizing principles. The two of us have jointly enjoyed a highly varied and engrossing career in biophysical research over nearly 50 years. Our frequent changes of emphasis are tied together by two threads: first, by finding the right names, visualizations, and methods to help both ourselves and others to better understand the 3D structures of protein and RNA molecules, and second, by redefining the boundary between signal and noise for complex data, in both directions-sometimes identifying and promoting real signal up out of what seemed just noise, and sometimes demoting apparent signal into noise or systematic error. Here we relate parts of our scientific and personal lives, including ups and downs, influences, anecdotes, and guiding principles such as the title theme.
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Affiliation(s)
- Jane S. Richardson
- Department of Biochemistry, Duke University, Durham, North Carolina 27710;
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39
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Hung JE, Fogle EJ, Christman HD, Johannes TW, Zhao H, Metcalf WW, van der Donk WA. Investigation of the role of Arg301 identified in the X-ray structure of phosphite dehydrogenase. Biochemistry 2012; 51:4254-62. [PMID: 22564138 PMCID: PMC3361975 DOI: 10.1021/bi201691w] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
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Phosphite dehydrogenase (PTDH) from Pseudomonas
stutzeri catalyzes the nicotinamide adenine dinucleotide-dependent
oxidation
of phosphite to phosphate. The enzyme belongs to the family of d-hydroxy acid dehydrogenases (DHDHs). A search of the protein
databases uncovered many additional putative phosphite dehydrogenases.
The genes encoding four diverse candidates were cloned and expressed,
and the enzymes were purified and characterized. All oxidized phosphite
to phosphate and had similar kinetic parameters despite a low level
of pairwise sequence identity (39–72%). A recent crystal structure
identified Arg301 as a residue in the active site that has not been
investigated previously. Arg301 is fully conserved in the enzymes
shown here to be PTDHs, but the residue is not conserved in other
DHDHs. Kinetic analysis of site-directed mutants of this residue shows
that it is important for efficient catalysis, with an ∼100-fold
decrease in kcat and an almost 700-fold
increase in Km,phosphite for the R301A
mutant. Interestingly, the R301K mutant displayed a slightly higher kcat than the parent PTDH, and a more modest
increase in Km for phosphite (nearly 40-fold).
Given these results, Arg301 may be involved in the binding and orientation
of the phosphite substrate and/or play a catalytic role via electrostatic
interactions. Three other residues in the active site region that
are conserved in the PTDH orthologs but not DHDHs were identified
(Trp134, Tyr139, and Ser295). The importance of these residues was
also investigated by site-directed mutagenesis. All of the mutants
had kcat values similar to that of the
wild-type enzyme, indicating these residues are not important for
catalysis.
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Affiliation(s)
- John E Hung
- Department of Chemistry, University of Illinois, 600 South Mathews Avenue, Urbana, IL 61801, USA
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40
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Crystal structure and substrate-binding mode of a novel pectate lyase from alkaliphilic Bacillus sp. N16-5. Biochem Biophys Res Commun 2012; 420:269-74. [DOI: 10.1016/j.bbrc.2012.02.148] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 02/25/2012] [Indexed: 11/23/2022]
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41
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Khan S, Mian HS, Sandercock LE, Chirgadze NY, Pai EF. Crystal structure of the passenger domain of the Escherichia coli autotransporter EspP. J Mol Biol 2011; 413:985-1000. [PMID: 21964244 DOI: 10.1016/j.jmb.2011.09.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 09/08/2011] [Accepted: 09/14/2011] [Indexed: 10/17/2022]
Abstract
Autotransporters represent a large superfamily of known and putative virulence factors produced by Gram-negative bacteria. They consist of an N-terminal "passenger domain" responsible for the specific effector functions of the molecule and a C-terminal "β-domain" responsible for translocation of the passenger across the bacterial outer membrane. Here, we present the 2.5-Å crystal structure of the passenger domain of the extracellular serine protease EspP, produced by the pathogen Escherichia coli O157:H7 and a member of the serine protease autotransporters of Enterobacteriaceae (SPATEs). Like the previously structurally characterized SPATE passenger domains, the EspP passenger domain contains an extended right-handed parallel β-helix preceded by an N-terminal globular domain housing the catalytic function of the protease. Of note, however, is the absence of a second globular domain protruding from this β-helix. We describe the structure of the EspP passenger domain in the context of previous results and provide an alternative hypothesis for the function of the β-helix within SPATEs.
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Affiliation(s)
- Shekeb Khan
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, University Health Network, Toronto Medical Discovery Tower, Toronto, Ontario, Canada M5G 1L7
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42
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Efficient expression of an alkaline pectate lyase gene from Bacillus subtilis and the characterization of the recombinant protein. Biotechnol Lett 2011; 34:109-15. [PMID: 21915717 DOI: 10.1007/s10529-011-0734-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 08/24/2011] [Indexed: 10/17/2022]
Abstract
The gene encoding a novel alkaline pectate lyase (Apel) from Bacillus subtilis was cloned and expressed in B. subtilis WB600. Apel contained an ORF of 1,260 bp, encoding a signal peptide of 21 amino acids and a mature protein of 399 amino acids with a calculated molecular mass of 45497.9 Da. The mature Apel was structurally related to the enzymes in the polysaccharide lyase family 1. After purification, the recombinant Apel had a specific activity of 445 U mg(-1). The enzyme was optimally active at 50°C and pH 9.
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43
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Abbott DW, Gilbert HJ, Boraston AB. The active site of oligogalacturonate lyase provides unique insights into cytoplasmic oligogalacturonate beta-elimination. J Biol Chem 2010; 285:39029-38. [PMID: 20851883 DOI: 10.1074/jbc.m110.153981] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Oligogalacturonate lyases (OGLs; now also classified as pectate lyase family 22) are cytoplasmic enzymes found in pectinolytic members of Enterobacteriaceae, such as the enteropathogen Yersinia enterocolitica. OGLs utilize a β-elimination mechanism to preferentially catalyze the conversion of saturated and unsaturated digalacturonate into monogalacturonate and the 4,5-unsaturated monogalacturonate-like molecule, 5-keto-4-deoxyuronate. To provide mechanistic insights into the specificity of this enzyme activity, we have characterized the OGL from Y. enterocolitica, YeOGL, on oligogalacturonides and determined its three-dimensional x-ray structure to 1.65 Å. The model contains a Mn(2+) atom in the active site, which is coordinated by three histidines, one glutamine, and an acetate ion. The acetate mimics the binding of the uronate group of galactourono-configured substrates. These findings, in combination with enzyme kinetics and metal supplementation assays, provide a framework for modeling the active site architecture of OGL. This enzyme appears to contain a histidine for the abstraction of the α-proton in the -1 subsite, a residue that is highly conserved throughout the OGL family and represents a unique catalytic base among pectic active lyases. In addition, we present a hypothesis for an emerging relationship observed between the cellular distribution of pectate lyase folding and the distinct metal coordination chemistries of pectate lyases.
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Affiliation(s)
- D Wade Abbott
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, USA.
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44
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Garron ML, Cygler M. Structural and mechanistic classification of uronic acid-containing polysaccharide lyases. Glycobiology 2010; 20:1547-73. [PMID: 20805221 DOI: 10.1093/glycob/cwq122] [Citation(s) in RCA: 183] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Polysaccharide lyases (PLs) have been assigned to 21 families based on their sequences, with ~ 50 singletons awaiting further classification. For 19 of these families, the structure of at least one protein is known. In this review, we have analyzed the available structural information and show that presently known PL families belong to six general folds. Only two general catalytic mechanisms have been observed among these PLs: (1) metal-assisted neutralization of the acidic group of the sugar next to the cleaved bond, with, rather unusually, arginine or lysine playing the role of Brønsted base and (2) neutralization of the acidic group on the sugar by a close approach of an amino or acidic group forcing its protonation and Tyr or Tyr-His acting as the Brønsted base and acid.
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Affiliation(s)
- Marie-Line Garron
- Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
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45
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Basu S, Roy A, Ghosh A, Bera A, Chattopadhyay D, Chakrabarti K. Arg235 is an essential catalytic residue of Bacillus pumilus DKS1 pectate lyase to degum ramie fibre. Biodegradation 2010; 22:153-61. [DOI: 10.1007/s10532-010-9384-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 06/23/2010] [Indexed: 10/19/2022]
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46
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Thompson JE, Pourhossein M, Waterhouse A, Hudson T, Goldrick M, Derrick JP, Roberts IS. The K5 lyase KflA combines a viral tail spike structure with a bacterial polysaccharide lyase mechanism. J Biol Chem 2010; 285:23963-9. [PMID: 20519506 DOI: 10.1074/jbc.m110.127571] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
K5 lyase A (KflA) is a tail spike protein (TSP) encoded by a K5A coliphage, which cleaves K5 capsular polysaccharide, a glycosaminoglycan with the repeat unit [-4)-betaGlcA-(1,4)- alphaGlcNAc(1-], displayed on the surface of Escherichia coli K5 strains. The crystal structure of KflA reveals a trimeric arrangement, with each monomer containing a right-handed, single-stranded parallel beta-helix domain. Stable trimer formation by the intertwining of strands in the C-terminal domain, followed by proteolytic maturation, is likely to be catalyzed by an autochaperone as described for K1F endosialidase. The structure of KflA represents the first bacteriophage tail spike protein combining polysaccharide lyase activity with a single-stranded parallel beta-helix fold. We propose a catalytic site and mechanism representing convergence with the syn-beta-elimination site of heparinase II from Pedobacter heparinus.
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Affiliation(s)
- James E Thompson
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
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47
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Seyedarabi A, To TT, Ali S, Hussain S, Fries M, Madsen R, Clausen MH, Teixteira S, Brocklehurst K, Pickersgill RW. Structural insights into substrate specificity and the anti beta-elimination mechanism of pectate lyase. Biochemistry 2010; 49:539-46. [PMID: 20000851 DOI: 10.1021/bi901503g] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pectate lyases harness anti beta-elimination chemistry to cleave the alpha-1,4 linkage in the homogalacturonan region of plant cell wall pectin. We have studied the binding of five pectic oligosaccharides to Bacillus subtilis pectate lyase in crystals of the inactive enzyme in which the catalytic base is substituted with alanine (R279A). We discover that the three central subsites (-1, +1, and +2) have a profound preference for galacturonate but that the distal subsites can accommodate methylated galacturonate. It is reasonable to assume therefore that pectate lyase can cleave pectin with three consecutive galacturonate residues. The enzyme in the absence of substrate binds a single calcium ion, and we show that two additional calcium ions bind between enzyme and substrate carboxylates occupying the +1 subsite in the Michaelis complex. The substrate binds less intimately to the enzyme in a complex made with a catalytic base in place but in the absence of the calcium ions and an adjacent lysine. In this complex, the catalytic base is correctly positioned to abstract the C5 proton, but there are no calcium ions binding the carboxylate at the +1 subsite. It is clear, therefore, that the catalytic calcium ions and adjacent lysine promote catalysis by acidifying the alpha-proton, facilitating its abstraction by the base. There is also clear evidence that binding distorts the relaxed 2(1) or 3(1) helical conformation of the oligosaccharides in the region of the scissile bond.
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Affiliation(s)
- Arefeh Seyedarabi
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
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48
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Pijning T, van Pouderoyen G, Kluskens L, van der Oost J, Dijkstra BW. The crystal structure of a hyperthermoactive exopolygalacturonase fromThermotoga maritimareveals a unique tetramer. FEBS Lett 2009; 583:3665-70. [DOI: 10.1016/j.febslet.2009.10.047] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 10/15/2009] [Accepted: 10/15/2009] [Indexed: 12/15/2022]
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49
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50
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Cloning of the Trichoderma reesei cDNA encoding a glucuronan lyase belonging to a novel polysaccharide lyase family. Appl Environ Microbiol 2008; 75:101-7. [PMID: 18978091 DOI: 10.1128/aem.01749-08] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The filamentous fungus Trichoderma reesei produces glucuronan lyase (TrGL) when it is grown on beta-(1-->4)-polyglucuronate (cellouronate) as a sole carbon source. The cDNA encoding TrGL was cloned, and the recombinant enzyme was heterologously expressed in Pichia pastoris. The cDNA of TrGL includes a 777-bp open reading frame encoding a 20-amino-acid signal peptide and the 238-amino-acid mature protein. The amino acid sequence showed no similarity to the amino acid sequences of previously described functional proteins, indicating that the enzyme should be classified in a novel polysaccharide lyase (PL) family. Recombinant TrGL catalyzed depolymerization of cellouronate endolytically by beta-elimination and was highly specific for cellouronate. The enzyme was most active at pH 6.5 and 50 degrees C, and its activity and thermostability increased in the presence of Ca2+, suggesting that its calcium dependence is similar to that of other PLs, such as pectate lyases.
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