1
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Doggwiler V, Lanz M, Lipps G, Imanidis G. Mechanistic Investigation of Enzyme Triggered Release from a Xyloglucan Matrix Tablet for Controlled Colonic Drug Delivery. J Pharm Sci 2024; 113:2524-2541. [PMID: 38796155 DOI: 10.1016/j.xphs.2024.05.020] [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: 01/25/2024] [Revised: 05/16/2024] [Accepted: 05/16/2024] [Indexed: 05/28/2024]
Abstract
The objective of this study was to investigate the mechanisms underlying drug release from a controlled colonic release (CCR) tablet formulation based on a xyloglucan polysaccharide matrix and identify the factors that control the rate of release for the purpose of fundamentally substantiating the concept and demonstrating its robustness for colonic drug delivery. Previous work demonstrated in vitro limited release of 5-aminosalicylic acid (5-ASA) and caffeine from these tablets in small intestinal environment and significant acceleration of release by xyloglucanase, an enzyme of the colonic microbiome. Targeted colonic drug delivery was verified in an animal study in vivo. In the present work, interaction of the xyloglucan matrix tablets with aqueous dissolution media containing xyloglucanase was found to lead to the spontaneous formation of a hydrated highly viscous gummy layer at the surface of the matrix which had a reduced drug content compared to the underlying regions and persisted with a nearly constant thickness that was inversely correlated to the enzyme concentration throughout the duration of the release process. Enzymatic hydrolysis of xyloglucan was determined to take place at the surface of the matrix leading to matrix erosion and a relation for the rate of enzymatic reaction as a function of bulk enzyme concentration and the concentration of dissolved xyloglucan in the gummy layer was derived. A mathematical model was developed encompassing aqueous medium ingress, matrix metamorphosis due to xyloglucan dissolution and matrix swelling, enzymatic hydrolysis of the polysaccharide and concomitant drug release due to matrix erosion and simultaneous drug diffusion. The model was fitted to data of reducing sugar equivalents in the medium reflecting matrix erosion and released drug amount. Enzymatic reaction parameters and reasonable values of medium ingress velocity, xyloglucan dissolution rate constant and drug diffusion coefficient were deduced that provided an adequate approximation of the data. Erosion was shown to be the overwhelmingly dominant drug release mechanism while the role of diffusion marginally increased at low enzyme concentration and high drug solubility. Changing enzyme concentration had a rather weak effect on matrix erosion and drug release rate as demonstrated by model simulations supported by experimental data, while xyloglucan dissolution was slow and had a stronger effect on the rate of the process. Therefore, reproducible colonic drug delivery not critically influenced by inter- and intra-individual variation of microbial enzyme activity may be projected.
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Affiliation(s)
- Viviane Doggwiler
- School of Life Sciences, University of Applied Sciences Northwest Switzerland, Hofackerstrasse 30, 4132 Muttenz, Switzerland; Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Michael Lanz
- School of Life Sciences, University of Applied Sciences Northwest Switzerland, Hofackerstrasse 30, 4132 Muttenz, Switzerland
| | - Georg Lipps
- School of Life Sciences, University of Applied Sciences Northwest Switzerland, Hofackerstrasse 30, 4132 Muttenz, Switzerland
| | - Georgios Imanidis
- School of Life Sciences, University of Applied Sciences Northwest Switzerland, Hofackerstrasse 30, 4132 Muttenz, Switzerland; Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland.
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2
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Wannawong T, Mhuantong W, Macharoen P, Niemhom N, Sitdhipol J, Chaiyawan N, Umrung S, Tanasupawat S, Suwannarach N, Asami Y, Kuncharoen N. Comparative genomics reveals insight into the phylogeny and habitat adaptation of novel Amycolatopsis species, an endophytic actinomycete associated with scab lesions on potato tubers. FRONTIERS IN PLANT SCIENCE 2024; 15:1346574. [PMID: 38601305 PMCID: PMC11004387 DOI: 10.3389/fpls.2024.1346574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 03/07/2024] [Indexed: 04/12/2024]
Abstract
A novel endophytic actinomycete, strain MEP2-6T, was isolated from scab tissues of potato tubers collected from Mae Fag Mai Sub-district, San Sai District, Chiang Mai Province, Thailand. Strain MEP2-6T is a gram-positive filamentous bacteria characterized by meso-diaminopimelic acid in cell wall peptidoglycan and arabinose, galactose, glucose, and ribose in whole-cell hydrolysates. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and hydroxy-phosphatidylethanolamine were the major phospholipids, of which MK-9(H6) was the predominant menaquinone, whereas iso-C16:0 and iso-C15:0 were the major cellular fatty acids. The genome of the strain was 10,277,369 bp in size with a G + C content of 71.7%. The 16S rRNA gene phylogenetic and core phylogenomic analyses revealed that strain MEP2-6T was closely related to Amycolatopsis lexingtonensis NRRL B-24131T (99.4%), A. pretoriensis DSM 44654T (99.3%), and A. eburnea GLM-1T (98.9%). Notably, strain MEP2-6T displayed 91.7%, 91.8%, and 87% ANIb and 49%, 48.8%, and 35.4% dDDH to A. lexingtonensis DSM 44653T (=NRRL B-24131T), A. eburnea GLM-1T, and A. pretoriensis DSM 44654T, respectively. Based on phenotypic, chemotaxonomic, and genomic data, strain MEP2-6T could be officially assigned to a novel species within the genus Amycolatopsis, for which the name Amycolatopsis solani sp. nov. has been proposed. The type of strain is MEP2-6T (=JCM 36309T = TBRC 17632T = NBRC 116395T). Amycolatopsis solani MEP2-6T was strongly proven to be a non-phytopathogen of potato scab disease because stunting of seedlings and necrotic lesions on potato tuber slices were not observed, and there were no core biosynthetic genes associated with the BGCs of phytotoxin-inducing scab lesions. Furthermore, comparative genomics can provide a better understanding of the genetic mechanisms that enable A. solani MEP2-6T to adapt to the plant endosphere. Importantly, the strain smBGCs accommodated 33 smBGCs encoded for several bioactive compounds, which could be beneficially applied in the fields of agriculture and medicine. Consequently, strain MEP2-6T is a promising candidate as a novel biocontrol agent and antibiotic producer.
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Affiliation(s)
- Thippawan Wannawong
- Department of Plant Pathology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Wuttichai Mhuantong
- Food Biotechnology Research Team, Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani, Thailand
- Enzyme Technology Research Team, Biorefinery and Bioproducts Technology Research Group, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Pipat Macharoen
- Department of Plant Pathology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Nantawan Niemhom
- Microbiological and Molecular Biological Laboratory, Scientific Instruments Center, School of Science, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, Thailand
| | - Jaruwan Sitdhipol
- Biodiversity Research Centre, Research and Development Group for Bio-Industries, Thailand Institute of Scientific and Technological Research, Pathum Thani, Thailand
| | - Neungnut Chaiyawan
- Biodiversity Research Centre, Research and Development Group for Bio-Industries, Thailand Institute of Scientific and Technological Research, Pathum Thani, Thailand
| | - Sarinna Umrung
- Department of Plant Pathology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Somboon Tanasupawat
- Department of Biochemistry and Microbiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Nakarin Suwannarach
- Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai, Thailand
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
| | - Yukihiro Asami
- Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan
- Ōmura Satoshi Memorial Institute, Kitasato University, Tokyo, Japan
| | - Nattakorn Kuncharoen
- Department of Plant Pathology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
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3
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Doggwiler V, Lanz M, Paredes V, Lipps G, Imanidis G. Tablet formulation with dual control concept for efficient colonic drug delivery. Int J Pharm 2023; 631:122499. [PMID: 36529358 DOI: 10.1016/j.ijpharm.2022.122499] [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: 09/27/2022] [Revised: 12/10/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Aim of this study was to develop a tablet formulation for targeted colonic drug release by implementing two control mechanisms: A pH-sensitive coating layer based on Eudragit® FS 30 D to prevent drug release in the upper gastrointestinal tract, combined with a matrix based on plant-derived polysaccharide xyloglucan to inhibit drug release after coating removal in the small intestine and to allow microbiome triggered drug release in the colon. In vitro dissolution tests simulated the passage through the entire gastrointestinal tract with a four-stage protocol, including microbial xyloglucanase addition in physiologically relevant concentrations as microbiome surrogate to the colonic dissolution medium. Matrix erosion was monitored in parallel to drug release by measurement of reducing sugar equivalents resulting from xyloglucan hydrolysis. Limited drug release in gastric and small intestinal test stages and predominant release in the colonic stage was achieved. The xyloglucan matrix controlled drug release after dissolution of the enteric coating through the formation of a gummy polysaccharide layer at the tablet surface. Matrix degradation was dependent on enzyme concentration in the colonic medium and significantly accelerated drug release resulting in erosion-controlled release process. Drug release at physiologically relevant enzyme concentration was completed within the bounds of colonic transit time. The dual control concept was applicable to two drug substances with different solubility, providing similar release rates in colonic environment containing xyloglucanase. Drug solubility mechanistically affected release, with diffusion of caffeine, but not of 5-ASA, contributing to the overall release rate out of the matrix tablet.
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Affiliation(s)
- Viviane Doggwiler
- School of Life Sciences, University of Applied Sciences Northwestern Switzerland, Hofackerstrasse 30, 4132 Muttenz, Switzerland; Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Michael Lanz
- School of Life Sciences, University of Applied Sciences Northwestern Switzerland, Hofackerstrasse 30, 4132 Muttenz, Switzerland
| | - Valeria Paredes
- School of Life Sciences, University of Applied Sciences Northwestern Switzerland, Hofackerstrasse 30, 4132 Muttenz, Switzerland
| | - Georg Lipps
- School of Life Sciences, University of Applied Sciences Northwestern Switzerland, Hofackerstrasse 30, 4132 Muttenz, Switzerland
| | - Georgios Imanidis
- School of Life Sciences, University of Applied Sciences Northwestern Switzerland, Hofackerstrasse 30, 4132 Muttenz, Switzerland; Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland.
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4
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Glasgow EM, Kemna EI, Bingman CA, Ing N, Deng K, Bianchetti CM, Takasuka TE, Northen TR, Fox BG. A structural and kinetic survey of GH5_4 endoglucanases reveals determinants of broad substrate specificity and opportunities for biomass hydrolysis. J Biol Chem 2021; 295:17752-17769. [PMID: 33454012 DOI: 10.1074/jbc.ra120.015328] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 10/15/2020] [Indexed: 11/06/2022] Open
Abstract
Broad-specificity glycoside hydrolases (GHs) contribute to plant biomass hydrolysis by degrading a diverse range of polysaccharides, making them useful catalysts for renewable energy and biocommodity production. Discovery of new GHs with improved kinetic parameters or more tolerant substrate-binding sites could increase the efficiency of renewable bioenergy production even further. GH5 has over 50 subfamilies exhibiting selectivities for reaction with β-(1,4)-linked oligo- and polysaccharides. Among these, subfamily 4 (GH5_4) contains numerous broad-selectivity endoglucanases that hydrolyze cellulose, xyloglucan, and mixed-linkage glucans. We previously surveyed the whole subfamily and found over 100 new broad-specificity endoglucanases, although the structural origins of broad specificity remained unclear. A mechanistic understanding of GH5_4 substrate specificity would help inform the best protein design strategies and the most appropriate industrial application of broad-specificity endoglucanases. Here we report structures of 10 new GH5_4 enzymes from cellulolytic microbes and characterize their substrate selectivity using normalized reducing sugar assays and MS. We found that GH5_4 enzymes have the highest catalytic efficiency for hydrolysis of xyloglucan, glucomannan, and soluble β-glucans, with opportunistic secondary reactions on cellulose, mannan, and xylan. The positions of key aromatic residues determine the overall reaction rate and breadth of substrate tolerance, and they contribute to differences in oligosaccharide cleavage patterns. Our new composite model identifies several critical structural features that confer broad specificity and may be readily engineered into existing industrial enzymes. We demonstrate that GH5_4 endoglucanases can have broad specificity without sacrificing high activity, making them a valuable addition to the biomass deconstruction toolset.
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Affiliation(s)
- Evan M Glasgow
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, USA; Great Lakes Bioenergy Research Center, Madison, Wisconsin, USA
| | - Elias I Kemna
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, USA
| | - Craig A Bingman
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, USA; Great Lakes Bioenergy Research Center, Madison, Wisconsin, USA
| | - Nicole Ing
- Joint BioEnergy Institute, Emeryville, California, USA; Sandia National Laboratories, Livermore, California, USA
| | - Kai Deng
- Joint BioEnergy Institute, Emeryville, California, USA; Sandia National Laboratories, Livermore, California, USA
| | - Christopher M Bianchetti
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, USA; Great Lakes Bioenergy Research Center, Madison, Wisconsin, USA
| | | | - Trent R Northen
- Joint BioEnergy Institute, Emeryville, California, USA; Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Brian G Fox
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, USA; Great Lakes Bioenergy Research Center, Madison, Wisconsin, USA.
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Characterization of an alkali-stable xyloglucanase/mixed-linkage β-glucanase Pgl5A from Paenibacillus sp. S09. Int J Biol Macromol 2019; 140:1158-1166. [DOI: 10.1016/j.ijbiomac.2019.08.210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 08/24/2019] [Accepted: 08/24/2019] [Indexed: 11/15/2022]
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Metagenomic discovery of feruloyl esterases from rumen microflora. Appl Microbiol Biotechnol 2019; 103:8449-8457. [PMID: 31511934 DOI: 10.1007/s00253-019-10102-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 07/31/2019] [Accepted: 08/26/2019] [Indexed: 10/26/2022]
Abstract
Feruloyl esterases (FAEs) are a key group of enzymes that hydrolyze ferulic acids ester-linked to plant polysaccharides. The cow's rumen is a highly evolved ecosystem of complex microbial microflora capable of converting fibrous substances to energy. From direct cloning of the rumen microbial metagenome, we identified seven active phagemids conferring feruloyl esterase activity. The genomic inserts ranged from 1633 to 4143 bp, and the ORFs from 681 to 1359 bp. BLAST search reveals sequence homology to feruloyl esterases and esterases/lipases identified in anaerobes. The seven genes were expressed in Escherichia coli, and the proteins were purified to homogeneity. The FAEs were found to cover types B, C, and D in the feruloyl esterase classification system using model hydroxycinnamic acid esters. The release of ferulic acid (FA) catalyzed by these enzymes was established using natural substrates corn fiber (CF) and wheat insoluble arabinoxylan (WIA). Three of the enzymes were demonstrated to cleave diferulates and hence the capability to break down Araf-FA-FA-Araf cross-links. The wide variation in the sequence, activity, and substrate specificity observed in the FAEs discovered in this study is a confirming evidence that combined actions of a full range of FAE enzymes contribute to the high-efficiency fiber digestion in the rumen microbial ecosystem.
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7
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de Gouvêa PF, Gerolamo LE, Bernardi AV, Pereira LMS, Uyemura SA, Dinamarco TM. Lytic Polysaccharide Monooxygenase from Aspergillus fumigatus can Improve Enzymatic Cocktail Activity During Sugarcane Bagasse Hydrolysis. Protein Pept Lett 2019; 26:377-385. [DOI: 10.2174/0929866526666190228163629] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/13/2019] [Accepted: 02/13/2019] [Indexed: 12/12/2022]
Abstract
Background:
Lytic Polysaccharide Monooxygenases (LPMOs) are auxiliary accessory
enzymes that act synergistically with cellulases and which are increasingly being used in secondgeneration
bioethanol production from biomasses. Several LPMOs have been identified in various
filamentous fungi, including Aspergillus fumigatus. However, many LPMOs have not been characterized
yet.
Objective:
To report the role of uncharacterized A. fumigatus AfAA9_B LPMO.
Methods:
qRT-PCR analysis was employed to analyze the LPMO gene expression profile in different
carbon sources. The gene encoding an AfAA9_B (Afu4g07850) was cloned into the vector pET-
28a(+), expressed in the E. coli strain RosettaTM (DE3) pLysS, and purified by a Ni2+-nitrilotriacetic
(Ni-NTA) agarose resin. To evaluate the specific LPMO activity, the purified protein peroxidase
activity was assessed. The auxiliary LPMO activity was investigated by the synergistic activity in
Celluclast 1.5L enzymatic cocktail.
Results:
LPMO was highly induced in complex biomass like sugarcane bagasse (SEB), Avicel®
PH-101, and CM-cellulose. The LPMO gene encoded a protein comprising 250 amino acids, without
a CBM domain. After protein purification, the AfAA9_B molecular mass estimated by SDSPAGE
was 35 kDa. The purified protein specific peroxidase activity was 8.33 ± 1.9 U g-1. Upon
addition to Celluclast 1.5L, Avicel® PH-101 and SEB hydrolysis increased by 18% and 22%, respectively.
Conclusion:
A. fumigatus LPMO is a promising candidate to enhance the currently available enzymatic
cocktail and can therefore be used in second-generation ethanol production.
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Affiliation(s)
- Paula Fagundes de Gouvêa
- Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Luis Eduardo Gerolamo
- Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Aline Vianna Bernardi
- Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Lucas Matheus Soares Pereira
- Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Sergio Akira Uyemura
- Faculdade de Ciencias Farmaceuticas de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - Taisa Magnani Dinamarco
- Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
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8
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Shang M, Chan VJ, Wong DWS, Liao H. A novel method for rapid and sensitive metagenomic activity screening. MethodsX 2018. [PMID: 30003051 DOI: 10.1016/j.mex.2018.06.011)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Direct cloning of metagenomes has proven to be a powerful tool for the exploration of the diverse sequence space of a microbial community leading to gene discovery and biocatalyst development. The key to such approach is the development of rapid, sensitive, and reliable functional screening of libraries. The majority of library screen have relied on the use of agar plates in petri dishes incorporating the target enzyme substrate for activity detection of positive clones (Iqbal et al. [1], Knietsch et al. [2], Popovic et al. [3]). In this article, a novel method is described consisting of: (1) formulation and application of substrate gel microtiter assay plates, (2) screening of libraries of clones in split pools in the wells of the assay plate, and (3) progressive enrichment and isolation of individual positive clones. The method has been successfully used in the rapid discovery of novel genes and enzymes from rumen microbial metagenome with high efficacy. •Novel substrate gel assay plates for activity screening with localized and intensified signals.•Rapid and complete screening of library clones in split pools.•Progressive enrichment scheme as a refining step for isolating target gene.
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Affiliation(s)
- Meiling Shang
- Western Regional Research Center, USDA-ARS, Albany, CA, USA
| | - Victor J Chan
- Western Regional Research Center, USDA-ARS, Albany, CA, USA
| | | | - Hans Liao
- Cargill Biotechnology Development Center, Minneapolis, MN, USA
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Shang M, Chan VJ, Wong DWS, Liao H. A novel method for rapid and sensitive metagenomic activity screening. MethodsX 2018; 5:669-675. [PMID: 30003051 PMCID: PMC6039833 DOI: 10.1016/j.mex.2018.06.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/10/2018] [Indexed: 01/27/2023] Open
Abstract
Direct cloning of metagenomes has proven to be a powerful tool for the exploration of the diverse sequence space of a microbial community leading to gene discovery and biocatalyst development. The key to such approach is the development of rapid, sensitive, and reliable functional screening of libraries. The majority of library screen have relied on the use of agar plates in petri dishes incorporating the target enzyme substrate for activity detection of positive clones (Iqbal et al. [1], Knietsch et al. [2], Popovic et al. [3]). In this article, a novel method is described consisting of: (1) formulation and application of substrate gel microtiter assay plates, (2) screening of libraries of clones in split pools in the wells of the assay plate, and (3) progressive enrichment and isolation of individual positive clones. The method has been successfully used in the rapid discovery of novel genes and enzymes from rumen microbial metagenome with high efficacy. •Novel substrate gel assay plates for activity screening with localized and intensified signals.•Rapid and complete screening of library clones in split pools.•Progressive enrichment scheme as a refining step for isolating target gene.
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Affiliation(s)
- Meiling Shang
- Western Regional Research Center, USDA-ARS, Albany, CA, USA
| | - Victor J Chan
- Western Regional Research Center, USDA-ARS, Albany, CA, USA
| | | | - Hans Liao
- Cargill Biotechnology Development Center, Minneapolis, MN, USA
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10
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Attia MA, Nelson CE, Offen WA, Jain N, Davies GJ, Gardner JG, Brumer H. In vitro and in vivo characterization of three Cellvibrio japonicus glycoside hydrolase family 5 members reveals potent xyloglucan backbone-cleaving functions. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:45. [PMID: 29467823 PMCID: PMC5816542 DOI: 10.1186/s13068-018-1039-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 02/01/2018] [Indexed: 05/15/2023]
Abstract
BACKGROUND Xyloglucan (XyG) is a ubiquitous and fundamental polysaccharide of plant cell walls. Due to its structural complexity, XyG requires a combination of backbone-cleaving and sidechain-debranching enzymes for complete deconstruction into its component monosaccharides. The soil saprophyte Cellvibrio japonicus has emerged as a genetically tractable model system to study biomass saccharification, in part due to its innate capacity to utilize a wide range of plant polysaccharides for growth. Whereas the downstream debranching enzymes of the xyloglucan utilization system of C. japonicus have been functionally characterized, the requisite backbone-cleaving endo-xyloglucanases were unresolved. RESULTS Combined bioinformatic and transcriptomic analyses implicated three glycoside hydrolase family 5 subfamily 4 (GH5_4) members, with distinct modular organization, as potential keystone endo-xyloglucanases in C. japonicus. Detailed biochemical and enzymatic characterization of the GH5_4 modules of all three recombinant proteins confirmed particularly high specificities for the XyG polysaccharide versus a panel of other cell wall glycans, including mixed-linkage beta-glucan and cellulose. Moreover, product analysis demonstrated that all three enzymes generated XyG oligosaccharides required for subsequent saccharification by known exo-glycosidases. Crystallographic analysis of GH5D, which was the only GH5_4 member specifically and highly upregulated during growth on XyG, in free, product-complex, and active-site affinity-labelled forms revealed the molecular basis for the exquisite XyG specificity among these GH5_4 enzymes. Strikingly, exhaustive reverse-genetic analysis of all three GH5_4 members and a previously biochemically characterized GH74 member failed to reveal a growth defect, thereby indicating functional compensation in vivo, both among members of this cohort and by other, yet unidentified, xyloglucanases in C. japonicus. Our systems-based analysis indicates distinct substrate-sensing (GH74, GH5E, GH5F) and attack-mounting (GH5D) functions for the endo-xyloglucanases characterized here. CONCLUSIONS Through a multi-faceted, molecular systems-based approach, this study provides a new insight into the saccharification pathway of xyloglucan utilization system of C. japonicus. The detailed structural-functional characterization of three distinct GH5_4 endo-xyloglucanases will inform future bioinformatic predictions across species, and provides new CAZymes with defined specificity that may be harnessed in industrial and other biotechnological applications.
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Affiliation(s)
- Mohamed A. Attia
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4 Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1 Canada
| | - Cassandra E. Nelson
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250 USA
| | - Wendy A. Offen
- Department of Chemistry, University of York, Heslington, York, YO10 5DD UK
| | - Namrata Jain
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4 Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1 Canada
| | - Gideon J. Davies
- Department of Chemistry, University of York, Heslington, York, YO10 5DD UK
| | - Jeffrey G. Gardner
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250 USA
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4 Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1 Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3 Canada
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, BC V6T 1Z4 Canada
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11
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Affiliation(s)
- R. Rashmi
- Institute of Bioinformatics and Applied Biotechnology, Bengaluru, India
| | - K. R. Siddalingamurthy
- Department of Biochemistry, Jnanabharathi Campus, Bangalore University, Bengaluru, India
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12
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Shah RK, Patel AK, Davla DM, Parikh IK, Subramanian RB, Patel KC, Jakhesara SJ, Joshi CG. Molecular cloning, heterologous expression, and functional characterization of a cellulolytic enzyme (Cel PRII) from buffalo rumen metagenome. 3 Biotech 2017; 7:257. [PMID: 28733938 DOI: 10.1007/s13205-017-0895-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/12/2017] [Indexed: 01/02/2023] Open
Abstract
A cellulase encoding gene, Cel PRII, was identified from Mehsani buffalo rumen metagenome, and cloned and expressed in Escherichia coli BL21(DE3)pLysS. The 1170 bp full length gene encodes a 389 residue polypeptide (Cel PRII) containing a catalytic domain belonging to glycosyl hydrolase (GH) 5 family. The fusion protein consisting of the Cel PRII, thioredoxin tag and 6x Histidine tag with predicted molecular weight of 63 kDa when recovered from inclusion bodies under denaturing conditions, exhibited cellulolytic activity against carboxymethyl cellulose (CMC). Recombinant Cel PRII was stable in the pH range 4.0-10.0 with pH optima 6.0. The optimal reaction temperature of Cel PRII was 30 °C with more than 50% of its activity retained at the temperatures ranging from 0 to 50 °C. Cel PRII exhibited enhanced enzymatic activity in the presence of Mn2+ ions and was inhibited in the presence of chelating agent EDTA. The K m and V max values for CMC were found to be 166 mg/mL and 1292 IU/mg, respectively. Cel PRII identified in the present study may act as an excellent candidate for industrial applications, and may aid in lignocellulosic biomass conversion because of its potential cellulolytic activity, thermostability, and excellent pH stability.
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Affiliation(s)
- Ravi K Shah
- Department of Animal Biotechnology, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand, Gujarat, 388110, India
- P. G. Department of Biosciences, Sardar Patel University, Bakrol, 388315, India
| | - Amrutlal K Patel
- Department of Animal Biotechnology, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand, Gujarat, 388110, India
- Hester Biosciences Ltd., Merda-Adraj, Kadi, 382728, India
| | - Deepti M Davla
- Department of Animal Biotechnology, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand, Gujarat, 388110, India
| | - Ishan K Parikh
- Department of Animal Biotechnology, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand, Gujarat, 388110, India
- Zydus Vaccine Technology Centre, Changodar, Ahmedabad, 382213, India
| | | | - Kamlesh C Patel
- P. G. Department of Biosciences, Sardar Patel University, Bakrol, 388315, India
| | - Subhash J Jakhesara
- Department of Animal Biotechnology, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand, Gujarat, 388110, India
| | - Chaitanya G Joshi
- Department of Animal Biotechnology, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand, Gujarat, 388110, India.
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13
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Xian L, Wang F, Yin X, Feng JX. Identification and characterization of an acidic and acid-stable endoxyloglucanase from Penicillium oxalicum. Int J Biol Macromol 2016; 86:512-8. [DOI: 10.1016/j.ijbiomac.2016.01.105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/27/2016] [Accepted: 01/28/2016] [Indexed: 12/16/2022]
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14
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Cheng J, Huang S, Jiang H, Zhang Y, Li L, Wang J, Fan C. Isolation and characterization of a non-specific endoglucanase from a metagenomic library of goat rumen. World J Microbiol Biotechnol 2015; 32:12. [DOI: 10.1007/s11274-015-1957-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 10/14/2015] [Indexed: 01/08/2023]
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15
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Dos Santos CR, Cordeiro RL, Wong DWS, Murakami MT. Structural basis for xyloglucan specificity and α-d-Xylp(1 → 6)-D-Glcp recognition at the -1 subsite within the GH5 family. Biochemistry 2015; 54:1930-42. [PMID: 25714929 DOI: 10.1021/acs.biochem.5b00011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
GH5 is one of the largest glycoside hydrolase families, comprising at least 20 distinct activities within a common structural scaffold. However, the molecular basis for the functional differentiation among GH5 members is still not fully understood, principally for xyloglucan specificity. In this work, we elucidated the crystal structures of two novel GH5 xyloglucanases (XEGs) retrieved from a rumen microflora metagenomic library, in the native state and in complex with xyloglucan-derived oligosaccharides. These results provided insights into the structural determinants that differentiate GH5 XEGs from parental cellulases and a new mode of action within the GH5 family related to structural adaptations in the -1 subsite. The oligosaccharide found in the XEG5A complex, permitted the mapping, for the first time, of the positive subsites of a GH5 XEG, revealing the importance of the pocket-like topology of the +1 subsite in conferring the ability of some GH5 enzymes to attack xyloglucan. Complementarily, the XEG5B complex covered the negative subsites, completing the subsite mapping of GH5 XEGs at high resolution. Interestingly, XEG5B is, to date, the only GH5 member able to cleave XXXG into XX and XG, and in the light of these results, we propose that a modification in the -1 subsite enables the accommodation of a xylosyl side chain at this position. The stereochemical compatibility of the -1 subsite with a xylosyl moiety was also reported for other structurally nonrelated XEGs belonging to the GH74 family, indicating it to be an essential attribute for this mode of action.
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Affiliation(s)
- Camila Ramos Dos Santos
- †Brazilian Biosciences National Laboratory, National Center of Research in Energy and Materials, Campinas, São Paulo 13083-970, Brazil
| | - Rosa Lorizolla Cordeiro
- †Brazilian Biosciences National Laboratory, National Center of Research in Energy and Materials, Campinas, São Paulo 13083-970, Brazil
| | - Dominic W S Wong
- ‡Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710, United States
| | - Mário Tyago Murakami
- †Brazilian Biosciences National Laboratory, National Center of Research in Energy and Materials, Campinas, São Paulo 13083-970, Brazil
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16
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Feng T, Yan KP, Mikkelsen MD, Meyer AS, Schols HA, Westereng B, Mikkelsen JD. Characterisation of a novel endo-xyloglucanase (XcXGHA) from Xanthomonas that accommodates a xylosyl-substituted glucose at subsite -1. Appl Microbiol Biotechnol 2014; 98:9667-79. [PMID: 24898632 DOI: 10.1007/s00253-014-5825-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 05/08/2014] [Accepted: 05/10/2014] [Indexed: 11/26/2022]
Abstract
A xyloglucan-specific endo-1,4β-glucanase (XcXGHA) from Xanthomonas citri pv. mangiferaeindicae has been cloned, expressed in Escherichia coli, purified and characterised. The XcXGHA enzyme belongs to CAZy family GH74 and has catalytic site residues conserved with other xyloglucanases in this family. At its optimal reaction conditions, pH 7.0 and 40 °C, the enzyme has a k cat/K M value of 2.2 × 10(7) min(-1) M(-1) on a tamarind seed xyloglucan substrate. XcXGHA is relatively stable within a broad pH range (pH 4-9) and up to 50 °C (t 1/2, 50 °C of 74 min). XcXGHA is proven to be xyloglucan-specific, and a glycan microarray study verifies that XcXGHA catalyses cleavage of xyloglucan extracted from both monocot and dicot plant species. The enzyme catalyses hydrolysis of tamarind xyloglucan in a unique way by cleaving XXXG into XX and XG (X is xylosyl-substituted glucose; G is unsubstituted glucose), is able to degrade more complex xyloglucans and notably is able to cleave near more substituted xyloglucan motifs such as L [i.e. α-L-Fucp-(1 → 2)-β-D-Galp-(1 → 2)-α-D-Xylp-(1 → 6)-β-D-Glcp]. LC-MS/MS analysis of product profiles of tamarind xyloglucan which had been catalytically degraded by XcXGHA revealed that XcXGHA has specificity for X in subsite -1. The 3D model suggests that XcXGHA consists of two seven-bladed β-propeller domains with the catalytic center formed by the interface of these two domains, which is conserved in xyloglucanases in the GH74 family. However, the XcXGHA has two amino acids (D264 and R472) that differ from the conserved residues of other GH74 xyloglucanases. These two amino acids were predicted to be located on the opposite side of the active site pocket, facing each other and forming a closing surface above the active site pocket. These two amino acids may contribute to the unique substrate specificity of the XcXGHA enzyme.
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Affiliation(s)
- Tao Feng
- Center for BioProcess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 229, 2800 Kgs, Lyngby, Denmark
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17
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Lacombe-Harvey MÈ, Fortin M, Ohnuma T, Fukamizo T, Letzel T, Brzezinski R. A highly conserved arginine residue of the chitosanase from Streptomyces sp. N174 is involved both in catalysis and substrate binding. BMC BIOCHEMISTRY 2013; 14:23. [PMID: 24041306 PMCID: PMC3848431 DOI: 10.1186/1471-2091-14-23] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/11/2013] [Indexed: 01/24/2023]
Abstract
Background Streptomyces sp. N174 chitosanase (CsnN174), a member of glycoside hydrolases family 46, is one of the most extensively studied chitosanases. Previous studies allowed identifying several key residues of this inverting enzyme, such as the two catalytic carboxylic amino acids as well as residues that are involved in substrate binding. In spite of the progress in understanding the catalytic mechanism of this chitosanase, the function of some residues highly conserved throughout GH46 family has not been fully elucidated. This study focuses on one of such residues, the arginine 42. Results Mutation of Arg42 into any other amino acid resulted in a drastic loss of enzyme activity. Detailed investigations of R42E and R42K chitosanases revealed that the mutant enzymes are not only impaired in their catalytic activity but also in their mode of interaction with the substrate. Mutated enzymes were more sensitive to substrate inhibition and were altered in their pattern of activity against chitosans of various degrees of deacetylation. Our data show that Arg42 plays a dual role in CsnN174 activity. Conclusions Arginine 42 is essential to maintain the enzymatic function of chitosanase CsnN174. We suggest that this arginine is influencing the catalytic nucleophile residue and also the substrate binding mode of the enzyme by optimizing the electrostatic interaction between the negatively charged carboxylic residues of the substrate binding cleft and the amino groups of GlcN residues in chitosan.
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Affiliation(s)
- Marie-Ève Lacombe-Harvey
- Département de Biologie, Centre d'Étude et de Valorisation de la Diversité Microbienne, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.
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18
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Song S, Tang Y, Yang S, Yan Q, Zhou P, Jiang Z. Characterization of two novel family 12 xyloglucanases from the thermophilic Rhizomucor miehei. Appl Microbiol Biotechnol 2013; 97:10013-24. [DOI: 10.1007/s00253-013-4770-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 02/06/2013] [Accepted: 02/10/2013] [Indexed: 11/30/2022]
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19
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Wong DWS, Chan VJ, Liao H, Zidwick MJ. Cloning of a novel feruloyl esterase gene from rumen microbial metagenome and enzyme characterization in synergism with endoxylanases. J Ind Microbiol Biotechnol 2013; 40:287-95. [PMID: 23408035 DOI: 10.1007/s10295-013-1234-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 01/20/2013] [Indexed: 11/25/2022]
Abstract
A feruloyl esterase (FAE) gene was isolated from a rumen microbial metagenome, cloned into E. coli, and expressed in active form. The enzyme (RuFae2) was identified as a type C feruloyl esterase. The RuFae2 alone released ferulic acid from rice bran, wheat bran, wheat-insoluble arabinoxylan, corn fiber, switchgrass, and corn bran in the order of decreasing activity. Using a saturating amount of RuFae2 for 100 mg substrate, a maximum of 18.7 and 80.0 μg FA was released from 100 mg corn fiber and wheat-insoluble arabinoxylan, respectively. Addition of GH10 endoxylanase (EX) synergistically increased the release of FA with the highest level of 6.7-fold for wheat bran. The synergistic effect of adding GH11 EX was significantly smaller with all the substrates tested. The difference in the effect of the two EXs was further analyzed by comparing the rate in the release of FA with increasing EX concentration using wheat-insoluble arabinoxylan as the substrate.
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20
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Mechanistic insights into the inhibition of endo-β 1,4 xyloglucan hydrolase by a classical aspartic protease inhibitor. J Fluoresc 2012; 23:311-21. [PMID: 23212130 DOI: 10.1007/s10895-012-1149-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 11/20/2012] [Indexed: 10/27/2022]
Abstract
This is the first report of inactivation of xyloglucanase from Thermomonospora sp by pepstatin A, a specific inhibitor towards aspartic proteases. The steady state kinetics revealed a reversible, competitive, two-step inhibition mechanism with IC 50 and K i values of 3.5 ± 0.5 μM and 1.25 ± 0.5 μM respectively. The rate constants determined for the isomerization of EI to EI(*) and the dissociation of EI* were 14.5 ± 1.5 × 10(-5) s(-1) and 2.85 ± 1.2 × 10(-8) s(-1) respectively, whereas the overall inhibition constant K i(*) was 27 ± 1 nM. The conformational changes induced upon inhibitor binding to xyloglucanase were monitored by fluorescence analysis and the rate constants derived were in agreement with the kinetic data. The abolished isoindole fluorescence of o-phthalaldehyde (OPTA)-labeled xyloglucanase and far UV analysis suggested that pepstatin binds to the active site of the enzyme. Our results revealed that the inactivation of xyloglucanase is due to the interference in the electronic microenvironment and disruption of the hydrogen-bonding network between the essential histidine and other residues involved in catalysis.
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21
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Abstract
Meat and milk produced by ruminants are important agricultural products and are major sources of protein for humans. Ruminant production is of considerable economic value and underpins food security in many regions of the world. However, the sector faces major challenges because of diminishing natural resources and ensuing increases in production costs, and also because of the increased awareness of the environmental impact of farming ruminants. The digestion of feed and the production of enteric methane are key functions that could be manipulated by having a thorough understanding of the rumen microbiome. Advances in DNA sequencing technologies and bioinformatics are transforming our understanding of complex microbial ecosystems, including the gastrointestinal tract of mammals. The application of these techniques to the rumen ecosystem has allowed the study of the microbial diversity under different dietary and production conditions. Furthermore, the sequencing of genomes from several cultured rumen bacterial and archaeal species is providing detailed information about their physiology. More recently, metagenomics, mainly aimed at understanding the enzymatic machinery involved in the degradation of plant structural polysaccharides, is starting to produce new insights by allowing access to the total community and sidestepping the limitations imposed by cultivation. These advances highlight the promise of these approaches for characterising the rumen microbial community structure and linking this with the functions of the rumen microbiota. Initial results using high-throughput culture-independent technologies have also shown that the rumen microbiome is far more complex and diverse than the human caecum. Therefore, cataloguing its genes will require a considerable sequencing and bioinformatic effort. Nevertheless, the construction of a rumen microbial gene catalogue through metagenomics and genomic sequencing of key populations is an attainable goal. A rumen microbial gene catalogue is necessary to understand the function of the microbiome and its interaction with the host animal and feeds, and it will provide a basis for integrative microbiome-host models and inform strategies promoting less-polluting, more robust and efficient ruminants.
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22
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Abstract
The ability of β-glucanases to cleave xyloglucans, a family of highly decorated β-glucans ubiquitous in plant biomass, has traditionally been overlooked in functional biochemical studies. An emerging body of data indicates, however, that a spectrum of xyloglucan specificity resides in diverse glycoside hydrolases from a range of carbohydrate-active enzyme families-including classic "cellulase" families. This chapter outlines a series of enzyme kinetic and product analysis methods to establish degrees of xyloglucan specificity and modes of action of glycosidases emerging from enzyme discovery projects.
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Affiliation(s)
- Jens M Eklöf
- Michael Smith Laboratories and Department of Chemistry, University of British Columbia, Vancouver, Canada
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23
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Damásio ARL, Ribeiro LFC, Ribeiro LF, Furtado GP, Segato F, Almeida FBR, Crivellari AC, Buckeridge MS, Souza TACB, Murakami MT, Ward RJ, Prade RA, Polizeli MLTM. Functional characterization and oligomerization of a recombinant xyloglucan-specific endo-β-1,4-glucanase (GH12) from Aspergillus niveus. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1824:461-7. [PMID: 22230786 DOI: 10.1016/j.bbapap.2011.12.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 12/20/2011] [Accepted: 12/21/2011] [Indexed: 11/16/2022]
Abstract
Xyloglucan is a major structural polysaccharide of the primary (growing) cell wall of higher plants. It consists of a cellulosic backbone (beta-1,4-linked glucosyl residues) that is frequently substituted with side chains. This report describes Aspergillus nidulans strain A773 recombinant secretion of a dimeric xyloglucan-specific endo-β-1,4-glucanohydrolase (XegA) cloned from Aspergillus niveus. The ORF of the A. niveus xegA gene is comprised of 714 nucleotides, and encodes a 238 amino acid protein with a calculated molecular weight of 23.5kDa and isoelectric point of 4.38. The optimal pH and temperature were 6.0 and 60°C, respectively. XegA generated a xyloglucan-oligosaccharides (XGOs) pattern similar to that observed for cellulases from family GH12, i.e., demonstrating that its mode of action includes hydrolysis of the glycosidic linkages between glucosyl residues that are not branched with xylose. In contrast to commercial lichenase, mixed linkage beta-glucan (lichenan) was not digested by XegA, indicating that the enzyme did not cleave glucan β-1,3 or β-1,6 bonds. The far-UV CD spectrum of the purified enzyme indicated a protein rich in β-sheet structures as expected for GH12 xyloglucanases. Thermal unfolding studies displayed two transitions with mid-point temperatures of 51.3°C and 81.3°C respectively, and dynamic light scattering studies indicated that the first transition involves a change in oligomeric state from a dimeric to a monomeric form. Since the enzyme is a predominantly a monomer at 60°C, the enzymatic assays demonstrated that XegA is more active in its monomeric state.
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Affiliation(s)
- André R L Damásio
- Departamento de Bioquímica e Imunologia, Universidade de São Paulo, Ribeirão Preto, Brazil
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Pol D, Menon V, Rao M. Biochemical characterization of a novel thermostable xyloglucanase from an alkalothermophilic Thermomonospora sp. Extremophiles 2011; 16:135-46. [PMID: 22120834 DOI: 10.1007/s00792-011-0413-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 11/10/2011] [Indexed: 11/28/2022]
Abstract
Xyloglucanase from an extracellular culture filtrate of alkalothermophilic Thermomonospora sp. was purified to homogeneity with a molecular weight of 144 kDa as determined by SDS-PAGE and exhibited specificity towards xyloglucan with apparent K (m) of 1.67 mg/ml. The enzyme was active at a broad range of pH (5-8) and temperatures (40-80°C). The optimum pH and temperature were 7 and 70°C, respectively. The enzyme retained 100% activity at 50°C for 60 h with half-lives of 14 h, 6 h and 7 min at 60, 70 and 80°C, respectively. The kinetics of thermal denaturation revealed that the inactivation at 80°C is due to unfolding of the enzyme as evidenced by the distinct red shift in the wavelength maximum of the fluorescence profile. Xyloglucanase activity was positively modulated in the presence of Zn(2+), K(+), cysteine, β-mercaptoethanol and polyols. Thermostability was enhanced in the presence of additives (polyols and glycine) at 80°C. A hydrolysis of 55% for galactoxyloglucan (GXG) from tamarind kernel powder (TKP) was obtained in 12 h at 60°C and 6 h at 70°C using thermostable xyloglucanases, favouring a reduction in process time and enzyme dosage. The enzyme was stable in the presence of commercial detergents (Ariel), indicating its potential as an additive to laundry detergents.
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Affiliation(s)
- Dipali Pol
- Division of Biochemical Sciences, National Chemical Laboratory, Pune, India
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25
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Identification and characterization of a xyloglucan-specific family 74 glycosyl hydrolase from Streptomyces coelicolor A3(2). Appl Environ Microbiol 2011; 78:607-11. [PMID: 22101041 DOI: 10.1128/aem.06482-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The sco6545 gene of Streptomyces coelicolor A3(2) was nominated as a putative cellulase with 863 mature-form amino acids (90.58 kDa). We overexpressed and purified Sco6545 and demonstrated that the protein is not a cellulase but a xyloglucan-specific glycosyl hydrolase which cleaves xyloglucan at unbranched glucose residues.
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26
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Ariza A, Eklöf JM, Spadiut O, Offen WA, Roberts SM, Besenmatter W, Friis EP, Skjøt M, Wilson KS, Brumer H, Davies G. Structure and activity of Paenibacillus polymyxa xyloglucanase from glycoside hydrolase family 44. J Biol Chem 2011; 286:33890-900. [PMID: 21795708 PMCID: PMC3190823 DOI: 10.1074/jbc.m111.262345] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 07/12/2011] [Indexed: 11/06/2022] Open
Abstract
The enzymatic degradation of plant polysaccharides is emerging as one of the key environmental goals of the early 21st century, impacting on many processes in the textile and detergent industries as well as biomass conversion to biofuels. One of the well known problems with the use of nonstarch (nonfood)-based substrates such as the plant cell wall is that the cellulose fibers are embedded in a network of diverse polysaccharides, including xyloglucan, that renders access difficult. There is therefore increasing interest in the "accessory enzymes," including xyloglucanases, that may aid biomass degradation through removal of "hemicellulose" polysaccharides. Here, we report the biochemical characterization of the endo-β-1,4-(xylo)glucan hydrolase from Paenibacillus polymyxa with polymeric, oligomeric, and defined chromogenic aryl-oligosaccharide substrates. The enzyme displays an unusual specificity on defined xyloglucan oligosaccharides, cleaving the XXXG-XXXG repeat into XXX and GXXXG. Kinetic analysis on defined oligosaccharides and on aryl-glycosides suggests that both the -4 and +1 subsites show discrimination against xylose-appended glucosides. The three-dimensional structures of PpXG44 have been solved both in apo-form and as a series of ligand complexes that map the -3 to -1 and +1 to +5 subsites of the extended ligand binding cleft. Complex structures are consistent with partial intolerance of xylosides in the -4' subsites. The atypical specificity of PpXG44 may thus find use in industrial processes involving xyloglucan degradation, such as biomass conversion, or in the emerging exciting applications of defined xyloglucans in food, pharmaceuticals, and cellulose fiber modification.
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Affiliation(s)
- Antonio Ariza
- From the Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Jens M. Eklöf
- the Division of Glycoscience, School of Biotechnology, and
| | - Oliver Spadiut
- the Division of Glycoscience, School of Biotechnology, and
- Wallenberg Wood Science Center, Royal Institute of Technology, SE-106 91 Stockholm, Sweden, and
| | - Wendy A. Offen
- From the Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Shirley M. Roberts
- From the Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | | | | | | | - Keith S. Wilson
- From the Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Harry Brumer
- the Division of Glycoscience, School of Biotechnology, and
- Wallenberg Wood Science Center, Royal Institute of Technology, SE-106 91 Stockholm, Sweden, and
| | - Gideon Davies
- From the Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
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27
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Activity-based metagenomic screening and biochemical characterization of bovine ruminal protozoan glycoside hydrolases. Appl Environ Microbiol 2011; 77:8106-13. [PMID: 21948825 DOI: 10.1128/aem.05925-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The rumen, the foregut of herbivorous ruminant animals such as cattle, functions as a bioreactor to process complex plant material. Among the numerous and diverse microbes involved in ruminal digestion are the ruminal protozoans, which are single-celled, ciliated eukaryotic organisms. An activity-based screen was executed to identify genes encoding fibrolytic enzymes present in the metatranscriptome of a bovine ruminal protozoan-enriched cDNA expression library. Of the four novel genes identified, two were characterized in biochemical assays. Our results provide evidence for the effective use of functional metagenomics to retrieve novel enzymes from microbial populations that cannot be maintained in axenic cultures.
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