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Liu N, Odinot E, David H, Vita N, Otalvaro FM, Parsiegla G, Denis Y, Faulds C, Fierobe HP, Perret S. Intracellular removal of acetyl, feruloyl and p-coumaroyl decorations on arabinoxylo-oligosaccharides imported from lignocellulosic biomass degradation by Ruminiclostridium cellulolyticum. Microb Cell Fact 2024; 23:151. [PMID: 38789996 PMCID: PMC11127375 DOI: 10.1186/s12934-024-02423-z] [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: 02/13/2024] [Accepted: 05/13/2024] [Indexed: 05/26/2024] Open
Abstract
BACKGROUND Xylans are polysaccharides that are naturally abundant in agricultural by-products, such as cereal brans and straws. Microbial degradation of arabinoxylan is facilitated by extracellular esterases that remove acetyl, feruloyl, and p-coumaroyl decorations. The bacterium Ruminiclostridium cellulolyticum possesses the Xua (xylan utilization associated) system, which is responsible for importing and intracellularly degrading arabinoxylodextrins. This system includes an arabinoxylodextrins importer, four intracellular glycosyl hydrolases, and two intracellular esterases, XuaH and XuaJ which are encoded at the end of the gene cluster. RESULTS Genetic studies demonstrate that the genes xuaH and xuaJ are part of the xua operon, which covers xuaABCDD'EFGHIJ. This operon forms a functional unit regulated by the two-component system XuaSR. The esterases encoded at the end of the cluster have been further characterized: XuaJ is an acetyl esterase active on model substrates, while XuaH is a xylan feruloyl- and p-coumaryl-esterase. This latter is active on oligosaccharides derived from wheat bran and wheat straw. Modelling studies indicate that XuaH has the potential to interact with arabinoxylobiose acylated with mono- or diferulate. The intracellular esterases XuaH and XuaJ are believed to allow the cell to fully utilize the complex acylated arabinoxylo-dextrins imported into the cytoplasm during growth on wheat bran or straw. CONCLUSIONS This study reports for the first time that a cytosolic feruloyl esterase is part of an intracellular arabinoxylo-dextrin import and degradation system, completing its cytosolic enzymatic arsenal. This system represents a new pathway for processing highly-decorated arabinoxylo-dextrins, which could provide a competitive advantage to the cell and may have interesting biotechnological applications.
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Affiliation(s)
- Nian Liu
- Aix-Marseille Université, CNRS, LCB-UMR7283, Marseille, France
| | - Elise Odinot
- OléoInnov, 19 rue du Musée, Marseille, 13001, France
| | - Hélène David
- Aix-Marseille Université, CNRS, LCB-UMR7283, Marseille, France
| | - Nicolas Vita
- Aix-Marseille Université, CNRS, LCB-UMR7283, Marseille, France
| | - Felipe Mejia Otalvaro
- Technical University of Denmark, The Novo Nordisk Foundation Center for Biosustainability, Konges Lyngby, 2800, Denmark
| | - Goetz Parsiegla
- Aix-Marseille Université, CNRS, BIP-UMR7281, Marseille, France
| | - Yann Denis
- Aix-Marseille Université, CNRS, IMM, Marseille, France
| | - Craig Faulds
- Biodiversité et Biotechnologie Fongiques, INRAE, Aix Marseille University, Marseille, UMR1163, 13009, France
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Akram F, Fatima T, Ibrar R, Shabbir I, Shah FI, Haq IU. Trends in the development and current perspective of thermostable bacterial hemicellulases with their industrial endeavors: A review. Int J Biol Macromol 2024; 265:130993. [PMID: 38508567 DOI: 10.1016/j.ijbiomac.2024.130993] [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: 07/15/2023] [Revised: 03/12/2024] [Accepted: 03/17/2024] [Indexed: 03/22/2024]
Abstract
Hemicellulases are enzymes that hydrolyze hemicelluloses, common polysaccharides in nature. Thermophilic hemicellulases, derived from microbial strains, are extensively studied as natural biofuel sources due to the complex structure of hemicelluloses. Recent research aims to elucidate the catalytic principles, mechanisms and specificity of hemicellulases through investigations into their high-temperature stability and structural features, which have applications in biotechnology and industry. This review article targets to serve as a comprehensive resource, highlighting the significant progress in the field and emphasizing the vital role of thermophilic hemicellulases in eco-friendly catalysis. The primary goal is to improve the reliability of hemicellulase enzymes obtained from thermophilic bacterial strains. Additionally, with their ability to break down lignocellulosic materials, hemicellulases hold immense potential for biofuel production. Despite their potential, the commercial viability is hindered by their high enzyme costs, necessitating the development of efficient bioprocesses involving waste pretreatment with microbial consortia to overcome this challenge.
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Affiliation(s)
- Fatima Akram
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan.
| | - Taseer Fatima
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan
| | - Ramesha Ibrar
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan
| | - Ifrah Shabbir
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan
| | | | - Ikram Ul Haq
- Institute of Industrial Biotechnology, Government College University, Lahore 54000, Pakistan; Pakistan Academy of Sciences, Islamabad, Pakistan
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Fosses A, Franche N, Parsiegla G, Denis Y, Maté M, de Philip P, Fierobe HP, Perret S. Role of the Solute-Binding Protein CuaD in the Signaling and Regulating Pathway of Cellobiose and Cellulose Utilization in Ruminiclostridium cellulolyticum. Microorganisms 2023; 11:1732. [PMID: 37512904 PMCID: PMC10384115 DOI: 10.3390/microorganisms11071732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/30/2023] Open
Abstract
In Ruminiclostridium cellulolyticum, cellobiose is imported by the CuaABC ATP-binding cassette transporter containing the solute-binding protein (SBP) CuaA and is further degraded in the cytosol by the cellobiose phosphorylase CbpA. The genes encoding these proteins have been shown to be essential for cellobiose and cellulose utilization. Here, we show that a second SBP (CuaD), whose gene is adjacent to two genes encoding a putative two-component regulation system (CuaSR), forms a three-component system with CuaS and CuaR. Studies of mutant and recombinant strains of R. cellulolyticum have indicated that cuaD is important for the growth of strains on cellobiose and cellulose. Furthermore, the results of our RT-qPCR experiments suggest that both the three (CuaDSR)- and the two (CuaSR)-component systems are able to perceive the cellobiose signal. However, the strain producing the three-component system is more efficient in its cellobiose and cellulose utilization. As CuaD binds to CuaS, we propose an in-silico model of the complex made up of two extracellular domains of CuaS and two of CuaD. CuaD allows microorganisms to detect very low concentrations of cellobiose due to its high affinity and specificity for this disaccharide, and together with CuaSR, it triggers the expression of the cuaABC-cbpA genes involved in cellodextrins uptake.
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Affiliation(s)
| | | | | | - Yann Denis
- Aix Marseille Univ, CNRS, Plateforme Transcriptome, Marseille, France
| | - Maria Maté
- CNRS, Aix Marseille Univ, UMR7257 AFMB, Marseille, France
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Liu N, Gagnot S, Denis Y, Byrne D, Faulds C, Fierobe HP, Perret S. Selfish uptake versus extracellular arabinoxylan degradation in the primary degrader Ruminiclostridium cellulolyticum, a new string to its bow. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:127. [PMID: 36403068 PMCID: PMC9675976 DOI: 10.1186/s13068-022-02225-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Primary degraders of polysaccharides play a key role in anaerobic biotopes, where plant cell wall accumulates, providing extracellular enzymes to release fermentable carbohydrates to fuel themselves and other non-degrader species. Ruminiclostridium cellulolyticum is a model primary degrader growing amongst others on arabinoxylan. It produces large multi-enzymatic complexes called cellulosomes, which efficiently deconstruct arabinoxylan into fermentable monosaccharides. RESULTS Complete extracellular arabinoxylan degradation was long thought to be required to fuel the bacterium during this plant cell wall deconstruction stage. We discovered and characterized a second system of "arabinoxylan" degradation in R. cellulolyticum, which challenged this paradigm. This "selfish" system is composed of an ABC transporter dedicated to the import of large and possibly acetylated arabinoxylodextrins, and a set of four glycoside hydrolases and two esterases. These enzymes show complementary action modes on arabinoxylo-dextrins. Two α-L-arabinofuranosidases target the diverse arabinosyl side chains, and two exo-xylanases target the xylo-oligosaccharides backbone either at the reducing or the non-reducing end. Together, with the help of two different esterases removing acetyl decorations, they achieve the depolymerization of arabinoxylo-dextrins in arabinose, xylose and xylobiose. The in vivo study showed that this new system is strongly beneficial for the fitness of the bacterium when grown on arabinoxylan, leading to the conclusion that a part of arabinoxylan degradation is achieved in the cytosol, even if monosaccharides are efficiently provided by the cellulosomes in the extracellular space. These results shed new light on the strategies used by anaerobic primary degrader bacteria to metabolize highly decorated arabinoxylan in competitive environments. CONCLUSION The primary degrader model Ruminiclostridium cellulolyticum has developed a "selfish" strategy consisting of importing into the bacterium, large arabinoxylan-dextrin fractions released from a partial extracellular deconstruction of arabinoxylan, thus complementing its efficient extracellular arabinoxylan degradation system. Genetic studies suggest that this system is important to support fitness and survival in a competitive biotope. These results provide a better understanding of arabinoxylan catabolism in the primary degrader, with biotechnological application for synthetic microbial community engineering for the production of commodity chemicals from lignocellulosic biomass.
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Affiliation(s)
- Nian Liu
- Aix Marseille Univ, CNRS, LCB, Marseille, France, 31 chemin Joseph Aiguier F-13402, Marseille Cedex 20, Marseille, France
| | - Séverine Gagnot
- Aix Marseille Univ, CNRS, LCB, Marseille, France, 31 chemin Joseph Aiguier F-13402, Marseille Cedex 20, Marseille, France
| | - Yann Denis
- Aix Marseille Univ, CNRS, IMM, Marseille, France
| | | | - Craig Faulds
- INRAE, Aix Marseille Univ, INRAE, BBF, Marseille, France, 13009, Marseille, France
| | - Henri-Pierre Fierobe
- Aix Marseille Univ, CNRS, LCB, Marseille, France, 31 chemin Joseph Aiguier F-13402, Marseille Cedex 20, Marseille, France
| | - Stéphanie Perret
- Aix Marseille Univ, CNRS, LCB, Marseille, France, 31 chemin Joseph Aiguier F-13402, Marseille Cedex 20, Marseille, France.
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Geng B, Jia X, Peng X, Han Y. Biosynthesis of value-added bioproducts from hemicellulose of biomass through microbial metabolic engineering. Metab Eng Commun 2022; 15:e00211. [PMID: 36311477 PMCID: PMC9597109 DOI: 10.1016/j.mec.2022.e00211] [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: 08/04/2022] [Revised: 10/02/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
Hemicellulose is the second most abundant carbohydrate in lignocellulosic biomass and has extensive applications. In conventional biomass refinery, hemicellulose is easily converted to unwanted by-products in pretreatment and therefore can't be fully utilized. The present study aims to summarize the most recent development of lignocellulosic polysaccharide degradation and fully convert it to value-added bioproducts through microbial and enzymatic catalysis. Firstly, bioprocess and microbial metabolic engineering for enhanced utilization of lignocellulosic carbohydrates were discussed. The bioprocess for degradation and conversion of natural lignocellulose to monosaccharides and organic acids using anaerobic thermophilic bacteria and thermostable glycoside hydrolases were summarized. Xylose transmembrane transporting systems in natural microorganisms and the latest strategies for promoting the transporting capacity by metabolic engineering were summarized. The carbon catabolite repression effect restricting xylose utilization in microorganisms, and metabolic engineering strategies developed for co-utilization of glucose and xylose were discussed. Secondly, the metabolic pathways of xylose catabolism in microorganisms were comparatively analyzed. Microbial metabolic engineering for converting xylose to value-added bioproducts based on redox pathways, non-redox pathways, pentose phosphate pathway, and improving inhibitors resistance were summarized. Thirdly, strategies for degrading lignocellulosic polysaccharides and fully converting hemicellulose to value-added bioproducts through microbial metabolic engineering were proposed. Hemicellulose is the main carbohydrate of biomass and has valuable applications. Hemicellulose is underutilized in conventional biomass refinery and pretreatment. Microbial and enzymatic catalysis were applied for hemicellulose utilization. Xylose is converted to value-added bioproducts by metabolic engineering.
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Affiliation(s)
- Biao Geng
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China,School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaojing Jia
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China,School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaowei Peng
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China,School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yejun Han
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China,School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China,Corresponding author. National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
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Mauran S, Perera NT, Perera IC. MxyR of Mycobacterium tuberculosis Responds to Xylan; an Unusual Ligand for a MarR Family Transcriptional Regulator. Mol Biol 2021. [DOI: 10.1134/s0026893321050162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Sinha D, Banerjee S, Mandal S, Basu A, Banerjee A, Balachandran S, Chandra Mandal N, Chaudhury S. Enhanced biogas production from Lantana camara via bioaugmentation of cellulolytic bacteria. BIORESOURCE TECHNOLOGY 2021; 340:125652. [PMID: 34332446 DOI: 10.1016/j.biortech.2021.125652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/19/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
A study was designed to isolate cellulolytic bacteria from termite-gut and soil, optimizing their cellulase production to enhance biogas generation, using Lantana camara as a substrate. Out of 57 bacteria screened, two isolates DSB1 and DSB12, showed significant cellulolytic activity. 16S rRNA based methods identified these isolates as Microbacterium sp. and Arthrobacter sp. respectively. Maximum cellulase activity of 1.26 ± 0.044 U/ml and 1.31 ± 0.052 U/ml for DSB1 and DSB12 was observed at pH 7 and 7.2 under 35⁰C and 37⁰C, respectively. The L. camara biomass substrate with cow dung as an inoculum, bioaugmented with DSB1 and DSB12 separately, was tested for biogas production, producing 950 l/kg and 980 l/kg VS biogas with 57% and 60% methane, respectively. DSB1 and DSB12 revealed as potent cellulase producers that can be harnessed in the anaerobic digester for biomass conversion practices for enhanced biogas production.
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Affiliation(s)
- Debasree Sinha
- Department of Environmental Studies, Siksha -Bhavana, Visva-Bharati, Santiniketan, West Bengal, 731235, India
| | - Sandipan Banerjee
- Mycology and Plant Pathology Laboratory, Department of Botany, Siksha-Bhavana, Visva-Bharati, Santiniketan, West Bengal, 731235, India
| | - Subhrangshu Mandal
- Department of Botany, Siksha-Bhavana, Visva-Bharati, Santiniketan, Birbhum, West Bengal, 731235, India
| | - Aman Basu
- Department of Environmental Studies, Siksha -Bhavana, Visva-Bharati, Santiniketan, West Bengal, 731235, India; Department of Biology, York University, Toronto, Ontario, Canada
| | - Aishiki Banerjee
- Department of Environmental Studies, Siksha -Bhavana, Visva-Bharati, Santiniketan, West Bengal, 731235, India
| | - Srinivasan Balachandran
- Department of Environmental Studies, Siksha -Bhavana, Visva-Bharati, Santiniketan, West Bengal, 731235, India
| | - Narayan Chandra Mandal
- Mycology and Plant Pathology Laboratory, Department of Botany, Siksha-Bhavana, Visva-Bharati, Santiniketan, West Bengal, 731235, India
| | - Shibani Chaudhury
- Department of Environmental Studies, Siksha -Bhavana, Visva-Bharati, Santiniketan, West Bengal, 731235, India.
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Whole-Genome Sequence Data Analysis of Anoxybacillus kamchatkensis NASTPD13 Isolated from Hot Spring of Myagdi, Nepal. BIOMED RESEARCH INTERNATIONAL 2021; 2021:1869748. [PMID: 34258259 PMCID: PMC8257342 DOI: 10.1155/2021/1869748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 03/18/2021] [Accepted: 06/17/2021] [Indexed: 11/17/2022]
Abstract
Anoxybacillus kamchatkensis NASTPD13 isolated from Paudwar hot spring of Myagdi, Nepal, upon morphological and biochemical analysis revealed to be Gram-positive, straight or slightly curved, rod-shaped, spore-forming, catalase, and oxidase-positive facultative anaerobes. It grows over a wide range of pH (5.0-11) and temperature (37-75°C), which showed growth in different reduced carbon sources such as starch raffinose, glucose, fructose, inositol, trehalose, sorbitol, mellobiose, and mannitol in aerobic conditions. Furthermore, the partial sequence obtained upon sequencing showed 99% sequence similarity in 16S rRNA gene sequence with A. kamchatkensis JW/VK-KG4 and was suggested to be Anoxybacillus kamchatkensis. Moreover, whole-genome analysis of NASTPD13 revealed 2,866,796 bp genome with a G+C content of 41.6%. Analysis of the genome revealed the presence of 102 RNA genes, which includes sequences coding for 19 rRNA and 79 tRNA genes. While the 16S rRNA gene sequence of strain NASTPD13 showed high similarity (>99%) to those of A. kamchatkensis JW/VK-KG4, RAST analysis of NASTPD13 genome suggested that A. kamchatkensis G10 is actually the closest neighbor in terms of sequence similarity. The genome annotation by RAST revealed various genes encoding glycoside hydrolases supporting that it can utilize several reduced carbon sources as observed and these genes could be important for carbohydrate-related industries. Xylanase pathway, particularly the genomic region encoding key enzymes for xylan depolymerization and xylose metabolism, further confirmed the presence of the complete gene in xylan metabolism. In addition, the complete xylose utilization gene locus analysis of NASTPD13 genome revealed all including D-xylose transport ATP-binding protein XylG and XylF, the xylose isomerase encoding gene XylA, and the gene XylB coding for a xylulokinase supported the fact that the isolate contains a complete set of genes related to xylan degradation, pentose transport, and metabolism. The results of the present study suggest that the isolated A. kamchatkensis NASTPD13 containing xylanase-producing genes could be useful in lignocellulosic biomass-utilizing industries where pentose polymers could also be utilized along with the hexose polymers.
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Itoh T, Yaguchi M, Nakaichi A, Yoda M, Hibi T, Kimoto H. Structural characterization of two solute-binding proteins for N,N'-diacetylchitobiose/ N,N',N''-triacetylchitotoriose of the gram-positive bacterium, Paenibacillus sp. str. FPU-7. JOURNAL OF STRUCTURAL BIOLOGY-X 2021; 5:100049. [PMID: 34195603 PMCID: PMC8233162 DOI: 10.1016/j.yjsbx.2021.100049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 05/28/2021] [Indexed: 10/27/2022]
Abstract
The chitinolytic bacterium Paenibacillus sp. str. FPU-7 efficiently degrades chitin into oligosaccharides such as N-acetyl-D-glucosamine (GlcNAc) and disaccharides (GlcNAc)2 through multiple secretory chitinases. Transport of these oligosaccharides by P. str. FPU-7 has not yet been clarified. In this study, we identified nagB1, predicted to encode a sugar solute-binding protein (SBP), which is a component of the ABC transport system. However, the genes next to nagB1 were predicted to encode two-component regulatory system proteins rather than transmembrane domains (TMDs). We also identified nagB2, which is highly homologous to nagB1. Adjacent to nagB2, two genes were predicted to encode TMDs. Binding experiments of the recombinant NagB1 and NagB2 to several oligosaccharides using differential scanning fluorimetry and surface plasmon resonance confirmed that both proteins are SBPs of (GlcNAc)2 and (GlcNAc)3. We determined their crystal structures complexed with and without chitin oligosaccharides at a resolution of 1.2 to 2.0 Å. The structures shared typical SBP structural folds and were classified as subcluster D-I. Large domain motions were observed in the structures, suggesting that they were induced by ligand binding via the "Venus flytrap" mechanism. These structures also revealed chitin oligosaccharide recognition mechanisms. In conclusion, our study provides insight into the recognition and transport of chitin oligosaccharides in bacteria.
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Key Words
- ABC transporter
- ABC, ATP-binding cassette
- Chitin oligosaccharide
- DSF, differential scanning fluorimetry
- GH, glycoside hydrolase
- GlcN, D-glucosamine
- GlcNAc, N-acetyl-D-glucosamine
- OD600, optical density at 600 nm
- PDB, Protein Data Bank
- PTS, phosphoenolpyruvate phosphotransferase system
- Paenibacillus
- RU, response unit
- SBP, solute binding protein
- Se-Met, selenomethionine
- Solute binding protein
- TMD, transmembrane domain
- Two-component regulatory system
- a.a., amino acid
- r.m.s.d., root mean-square deviation
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Affiliation(s)
- Takafumi Itoh
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Matsuokakenjyoujima, Eiheiji-cho, Yoshida-gun, Fukui 910-1195, Japan
| | - Misaki Yaguchi
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Matsuokakenjyoujima, Eiheiji-cho, Yoshida-gun, Fukui 910-1195, Japan
| | - Akari Nakaichi
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Matsuokakenjyoujima, Eiheiji-cho, Yoshida-gun, Fukui 910-1195, Japan
| | - Moe Yoda
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Matsuokakenjyoujima, Eiheiji-cho, Yoshida-gun, Fukui 910-1195, Japan
| | - Takao Hibi
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Matsuokakenjyoujima, Eiheiji-cho, Yoshida-gun, Fukui 910-1195, Japan
| | - Hisashi Kimoto
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Matsuokakenjyoujima, Eiheiji-cho, Yoshida-gun, Fukui 910-1195, Japan
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Bing RG, Sulis DB, Wang JP, Adams MW, Kelly RM. Thermophilic microbial deconstruction and conversion of natural and transgenic lignocellulose. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:272-293. [PMID: 33684253 PMCID: PMC10519370 DOI: 10.1111/1758-2229.12943] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/25/2021] [Accepted: 02/28/2021] [Indexed: 06/12/2023]
Abstract
The potential to convert renewable plant biomasses into fuels and chemicals by microbial processes presents an attractive, less environmentally intense alternative to conventional routes based on fossil fuels. This would best be done with microbes that natively deconstruct lignocellulose and concomitantly form industrially relevant products, but these two physiological and metabolic features are rarely and simultaneously observed in nature. Genetic modification of both plant feedstocks and microbes can be used to increase lignocellulose deconstruction capability and generate industrially relevant products. Separate efforts on plants and microbes are ongoing, but these studies lack a focus on optimal, complementary combinations of these disparate biological systems to obtain a convergent technology. Improving genetic tools for plants have given rise to the generation of low-lignin lines that are more readily solubilized by microorganisms. Most focus on the microbiological front has involved thermophilic bacteria from the genera Caldicellulosiruptor and Clostridium, given their capacity to degrade lignocellulose and to form bio-products through metabolic engineering strategies enabled by ever-improving molecular genetics tools. Bioengineering plant properties to better fit the deconstruction capabilities of candidate consolidated bioprocessing microorganisms has potential to achieve the efficient lignocellulose deconstruction needed for industrial relevance.
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Affiliation(s)
- Ryan G. Bing
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695
| | - Daniel B. Sulis
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695
| | - Jack P. Wang
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695
| | - Michael W.W. Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Robert M. Kelly
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695
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Weng C, Peng X, Han Y. Depolymerization and conversion of lignin to value-added bioproducts by microbial and enzymatic catalysis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:84. [PMID: 33812391 PMCID: PMC8019502 DOI: 10.1186/s13068-021-01934-w] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/19/2021] [Indexed: 05/23/2023]
Abstract
Lignin, the most abundant renewable aromatic compound in nature, is an excellent feedstock for value-added bioproducts manufacturing; while the intrinsic heterogeneity and recalcitrance of which hindered the efficient lignin biorefinery and utilization. Compared with chemical processing, bioprocessing with microbial and enzymatic catalysis is a clean and efficient method for lignin depolymerization and conversion. Generally, lignin bioprocessing involves lignin decomposition to lignin-based aromatics via extracellular microbial enzymes and further converted to value-added bioproducts through microbial metabolism. In the review, the most recent advances in degradation and conversion of lignin to value-added bioproducts catalyzed by microbes and enzymes were summarized. The lignin-degrading microorganisms of white-rot fungi, brown-rot fungi, soft-rot fungi, and bacteria under aerobic and anaerobic conditions were comparatively analyzed. The catalytic metabolism of the microbial lignin-degrading enzymes of laccase, lignin peroxidase, manganese peroxidase, biphenyl bond cleavage enzyme, versatile peroxidase, and β-etherize was discussed. The microbial metabolic process of H-lignin, G-lignin, S-lignin based derivatives, protocatechuic acid, and catechol was reviewed. Lignin was depolymerized to lignin-derived aromatic compounds by the secreted enzymes of fungi and bacteria, and the aromatics were converted to value-added compounds through microbial catalysis and metabolic engineering. The review also proposes new insights for future work to overcome the recalcitrance of lignin and convert it to value-added bioproducts by microbial and enzymatic catalysis.
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Affiliation(s)
- Caihong Weng
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaowei Peng
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yejun Han
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
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12
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Duan R, Qiu L, Xu X, Ma Z, Merideth BR, Shyu CR, Zou X. Performance of human and server prediction in CAPRI rounds 38-45. Proteins 2020; 88:1110-1120. [PMID: 32483825 DOI: 10.1002/prot.25956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/26/2020] [Accepted: 05/27/2020] [Indexed: 11/11/2022]
Abstract
CAPRI challenges offer a variety of blind tests for protein-protein interaction prediction. In CAPRI Rounds 38-45, we generated a set of putative binding modes for each target with an FFT-based docking algorithm, and then scored and ranked these binding modes with a proprietary scoring function, ITScorePP. We have also developed a novel web server, Rebipp. The algorithm utilizes information retrieval to identify relevant biological information to significantly reduce the search space for a particular protein. In parallel, we have also constructed a GPU-based docking server, MDockPP, for protein-protein complex structure prediction. Here, the performance of our protocol in CAPRI rounds 38-45 is reported, which include 16 docking and scoring targets. Among them, three targets contain multiple interfaces: Targets 124, 125, and 136 have 2, 4, and 3 interfaces, respectively. In the predictor experiments, we predicted correct binding modes for nine targets, including one high-accuracy interface, six medium-accuracy binding modes, and six acceptable-accuracy binding modes. For the docking server prediction experiments, we predicted correct binding modes for eight targets, including one high-accuracy, three medium-accuracy, and five acceptable-accuracy binding modes.
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Affiliation(s)
- Rui Duan
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
| | - Liming Qiu
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
| | - Xianjin Xu
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
| | - Zhiwei Ma
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA.,Department of Physics and Astronomy, University of Missouri, Columbia, Missouri, USA
| | - Benjamin Ryan Merideth
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA.,Institute for Data Science and Informatics, University of Missouri, Columbia, Missouri, USA
| | - Chi-Ren Shyu
- Institute for Data Science and Informatics, University of Missouri, Columbia, Missouri, USA.,Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, Missouri, USA
| | - Xiaoqin Zou
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA.,Department of Physics and Astronomy, University of Missouri, Columbia, Missouri, USA.,Institute for Data Science and Informatics, University of Missouri, Columbia, Missouri, USA.,Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
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13
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Development of a thermophilic coculture for corn fiber conversion to ethanol. Nat Commun 2020; 11:1937. [PMID: 32321909 PMCID: PMC7176698 DOI: 10.1038/s41467-020-15704-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 03/25/2020] [Indexed: 12/27/2022] Open
Abstract
The fiber in corn kernels, currently unutilized in the corn to ethanol process, represents an opportunity for introduction of cellulose conversion technology. We report here that Clostridium thermocellum can solubilize over 90% of the carbohydrate in autoclaved corn fiber, including its hemicellulose component glucuronoarabinoxylan (GAX). However, Thermoanaerobacterium thermosaccharolyticum or several other described hemicellulose-fermenting thermophilic bacteria can only partially utilize this GAX. We describe the isolation of a previously undescribed organism, Herbinix spp. strain LL1355, from a thermophilic microbiome that can consume 85% of the recalcitrant GAX. We sequence its genome, and based on structural analysis of the GAX, identify six enzymes that hydrolyze GAX linkages. Combinations of up to four enzymes are successfully expressed in T. thermosaccharolyticum. Supplementation with these enzymes allows T. thermosaccharolyticum to consume 78% of the GAX compared to 53% by the parent strain and increases ethanol yield from corn fiber by 24%. Corn fiber is a difficult feedstock to utilize due to its recalcitrant hemicellulose. Here, the authors characterize the recalcitrant structures, isolate a new bacterium to consume the hemicellulose, identify its enzymes, and show the benefit with increased conversion of corn fiber to ethanol.
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14
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Cann I, Pereira GV, Abdel-Hamid AM, Kim H, Wefers D, Kayang BB, Kanai T, Sato T, Bernardi RC, Atomi H, Mackie RI. Thermophilic Degradation of Hemicellulose, a Critical Feedstock in the Production of Bioenergy and Other Value-Added Products. Appl Environ Microbiol 2020; 86:e02296-19. [PMID: 31980431 PMCID: PMC7082577 DOI: 10.1128/aem.02296-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Renewable fuels have gained importance as the world moves toward diversifying its energy portfolio. A critical step in the biomass-to-bioenergy initiative is deconstruction of plant cell wall polysaccharides to their unit sugars for subsequent fermentation to fuels. To acquire carbon and energy for their metabolic processes, diverse microorganisms have evolved genes encoding enzymes that depolymerize polysaccharides to their carbon/energy-rich building blocks. The microbial enzymes mostly target the energy present in cellulose, hemicellulose, and pectin, three major forms of energy storage in plants. In the effort to develop bioenergy as an alternative to fossil fuel, a common strategy is to harness microbial enzymes to hydrolyze cellulose to glucose for fermentation to fuels. However, the conversion of plant biomass to renewable fuels will require both cellulose and hemicellulose, the two largest components of the plant cell wall, as feedstock to improve economic feasibility. Here, we explore the enzymes and strategies evolved by two well-studied bacteria to depolymerize the hemicelluloses xylan/arabinoxylan and mannan. The sets of enzymes, in addition to their applications in biofuels and value-added chemical production, have utility in animal feed enzymes, a rapidly developing industry with potential to minimize adverse impacts of animal agriculture on the environment.
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Affiliation(s)
- Isaac Cann
- Department of Animal Science, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Microbiome Metabolic Engineering Theme, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto, Japan
| | - Gabriel V Pereira
- Department of Animal Science, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Microbiome Metabolic Engineering Theme, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Ahmed M Abdel-Hamid
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Microbiome Metabolic Engineering Theme, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Heejin Kim
- Microbiome Metabolic Engineering Theme, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Daniel Wefers
- Karlsruhe Institute of Technology, Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe, Germany
| | - Boniface B Kayang
- Department of Animal Science, School of Agriculture, University of Ghana, Legon, Ghana
| | - Tamotsu Kanai
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto, Japan
| | - Takaaki Sato
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto, Japan
- JST, CREST, Tokyo, Japan
| | - Rafael C Bernardi
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Haruyuki Atomi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto, Japan
- JST, CREST, Tokyo, Japan
| | - Roderick I Mackie
- Department of Animal Science, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Microbiome Metabolic Engineering Theme, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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15
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Characterization and diversity of the complete set of GH family 3 enzymes from Rhodothermus marinus DSM 4253. Sci Rep 2020; 10:1329. [PMID: 31992772 PMCID: PMC6987092 DOI: 10.1038/s41598-020-58015-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 01/07/2020] [Indexed: 11/08/2022] Open
Abstract
The genome of Rhodothermus marinus DSM 4253 encodes six glycoside hydrolases (GH) classified under GH family 3 (GH3): RmBgl3A, RmBgl3B, RmBgl3C, RmXyl3A, RmXyl3B and RmNag3. The biochemical function, modelled 3D-structure, gene cluster and evolutionary relationships of each of these enzymes were studied. The six enzymes were clustered into three major evolutionary lineages of GH3: β-N-acetyl-glucosaminidases, β-1,4-glucosidases/β-xylosidases and macrolide β-glucosidases. The RmNag3 with additional β-lactamase domain clustered with the deepest rooted GH3-lineage of β-N-acetyl-glucosaminidases and was active on acetyl-chitooligosaccharides. RmBgl3B displayed β-1,4-glucosidase activity and was the only representative of the lineage clustered with macrolide β-glucosidases from Actinomycetes. The β-xylosidases, RmXyl3A and RmXyl3B, and the β-glucosidases RmBgl3A and RmBgl3C clustered within the major β-glucosidases/β-xylosidases evolutionary lineage. RmXyl3A and RmXyl3B showed β-xylosidase activity with different specificities for para-nitrophenyl (pNP)-linked substrates and xylooligosaccharides. RmBgl3A displayed β-1,4-glucosidase/β-xylosidase activity while RmBgl3C was active on pNP-β-Glc and β-1,3-1,4-linked glucosyl disaccharides. Putative polysaccharide utilization gene clusters were also investigated for both R. marinus DSM 4253 and DSM 4252T (homolog strain). The analysis showed that in the homolog strain DSM 4252TRmar_1080 (RmXyl3A) and Rmar_1081 (RmXyl3B) are parts of a putative polysaccharide utilization locus (PUL) for xylan utilization.
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16
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Shi Q, Li Y, Li Y, Cheng Y, Zhu W. Effects of steam explosion on lignocellulosic degradation of, and methane production from, corn stover by a co-cultured anaerobic fungus and methanogen. BIORESOURCE TECHNOLOGY 2019; 290:121796. [PMID: 31319215 DOI: 10.1016/j.biortech.2019.121796] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/09/2019] [Accepted: 07/10/2019] [Indexed: 05/23/2023]
Abstract
The aim of this study was to investigate the effects of steam explosion on lignocellulose digestibility of, and methane production from corn stover by a co-culture of anaerobic fungus and methanogen. The cumulative methane production at 72 h of incubation from the steam-exploded corn stover was 32.2 ± 1.74 mL, which not significantly different (P > 0.05) from that of the untreated corn stover (37.1 ± 1.09 mL). However, steam explosion decreased the hemicellulose contents of corn stover by 28.0 ± 0.39% and increased the neutral detergent solute by 23.5 ± 0.25%. While this treatment did not affect the dry matter digestibility (64.1 ± 0.26%, and 64.1 ± 0.28%, respectively). In conclusion, the co-culture of anaerobic fungus and methanogen can degrade the crude fibrous portion of corn stover without any pretreatments. It possesses promising biotechnological prospects for conversion of crop residue based straw resources to obtain biofuel in the form of methane.
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Affiliation(s)
- Qicheng Shi
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuqi Li
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuanfei Li
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanfen Cheng
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China.
| | - Weiyun Zhu
- Laboratory of Gastrointestinal Microbiology, National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China
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17
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Chandravanshi M, Sharma A, Dasgupta P, Mandal SK, Kanaujia SP. Identification and characterization of ABC transporters for carbohydrate uptake in Thermus thermophilus HB8. Gene 2019; 696:135-148. [DOI: 10.1016/j.gene.2019.02.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/01/2019] [Indexed: 02/06/2023]
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18
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Fukamizo T, Kitaoku Y, Suginta W. Periplasmic solute-binding proteins: Structure classification and chitooligosaccharide recognition. Int J Biol Macromol 2019; 128:985-993. [PMID: 30771387 DOI: 10.1016/j.ijbiomac.2019.02.064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 01/12/2019] [Accepted: 02/11/2019] [Indexed: 12/17/2022]
Abstract
Periplasmic solute-binding proteins (SBPs) serve as molecular shuttles that assist the transport of small solutes from the outer membrane to the inner membrane of all Gram-negative bacteria. Based on the available crystal structures, SBPs are classified into seven clusters, A-G, and are further divided into subclusters, IV. This minireview is focused on the classification, structure and substrate specificity of a distinct class of SBPs specific for chitooligosaccharides (CBPs). To date, only two structures of CBP homologues, VhCBP and VcCBP, have been reported in the marine Vibrio species, with exposition of their limited function. The Vibrio CBPs are structurally classified as cluster C/subcluster IV SBPs that exclusively recognize β-1,4- or β-1,3-linked linear oligosaccharides. The overall structural feature of the Vibrios CBPs is most similar to the cellobiose-binding orthologue from the hyperthermophilic bacterium Thermotoga maritima. This similarity provides an opportunity to engineer the substrate specificity of the proteins and to control the uptake of chitinous and cellulosic nutrients in marine bacteria.
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Affiliation(s)
- Tamo Fukamizo
- Biochemistry and Electrochemistry Research Unit and School of Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Yoshihito Kitaoku
- Biochemistry and Electrochemistry Research Unit and School of Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Wipa Suginta
- Biochemistry and Electrochemistry Research Unit and School of Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand; School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Payupnai, Wangchan, Rayong 21210, Thailand.
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19
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Kim CC, Healey GR, Kelly WJ, Patchett ML, Jordens Z, Tannock GW, Sims IM, Bell TJ, Hedderley D, Henrissat B, Rosendale DI. Genomic insights from Monoglobus pectinilyticus: a pectin-degrading specialist bacterium in the human colon. ISME JOURNAL 2019; 13:1437-1456. [PMID: 30728469 PMCID: PMC6776006 DOI: 10.1038/s41396-019-0363-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 01/07/2019] [Accepted: 01/19/2019] [Indexed: 12/16/2022]
Abstract
Pectin is abundant in modern day diets, as it comprises the middle lamellae and one-third of the dry carbohydrate weight of fruit and vegetable cell walls. Currently there is no specialized model organism for studying pectin fermentation in the human colon, as our collective understanding is informed by versatile glycan-degrading bacteria rather than by specialist pectin degraders. Here we show that the genome of Monoglobus pectinilyticus possesses a highly specialized glycobiome for pectin degradation, unique amongst Firmicutes known to be in the human gut. Its genome encodes a simple set of metabolic pathways relevant to pectin sugar utilization, and its predicted glycobiome comprises an unusual distribution of carbohydrate-active enzymes (CAZymes) with numerous extracellular methyl/acetyl esterases and pectate lyases. We predict the M. pectinilyticus degradative process is facilitated by cell-surface S-layer homology (SLH) domain-containing proteins, which proteomics analysis shows are differentially expressed in response to pectin. Some of these abundant cell surface proteins of M. pectinilyticus share unique modular organizations rarely observed in human gut bacteria, featuring pectin-specific CAZyme domains and the cell wall-anchoring SLH motifs. We observed M. pectinilyticus degrades various pectins, RG-I, and galactan to produce polysaccharide degradation products (PDPs) which are presumably shared with other inhabitants of the human gut microbiome (HGM). This strain occupies a new ecological niche for a primary degrader specialized in foraging a habitually consumed plant glycan, thereby enriching our understanding of the diverse community profile of the HGM.
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Affiliation(s)
- Caroline C Kim
- The New Zealand Institute for Plant and Food Research, Palmerston North, 4474, New Zealand. .,Institute of Fundamental Sciences, Massey University, Palmerston North, 4442, New Zealand.
| | - Genelle R Healey
- The New Zealand Institute for Plant and Food Research, Palmerston North, 4474, New Zealand.,Massey Institute of Food Science and Technology, School of Food and Nutrition, Massey University, Palmerston North, New Zealand
| | | | - Mark L Patchett
- Institute of Fundamental Sciences, Massey University, Palmerston North, 4442, New Zealand
| | - Zoe Jordens
- Institute of Fundamental Sciences, Massey University, Palmerston North, 4442, New Zealand
| | - Gerald W Tannock
- Department of Microbiology and Immunology, Microbiome Otago, University of Otago, Dunedin, 9016, New Zealand
| | - Ian M Sims
- Ferrier Research Institute, Victoria University of Wellington, Gracefield Research Centre, Lower Hutt, 5040, New Zealand
| | - Tracey J Bell
- Ferrier Research Institute, Victoria University of Wellington, Gracefield Research Centre, Lower Hutt, 5040, New Zealand
| | - Duncan Hedderley
- The New Zealand Institute for Plant and Food Research, Palmerston North, 4474, New Zealand
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille University, Marseille, F-13288, France.,Institut National de la Recherche Agronomique, USC1408 Architecture et Fonction des Macromolécules Biologiques, Marseille, F-13288, France.,Department of Biological Sciences, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Douglas I Rosendale
- The New Zealand Institute for Plant and Food Research, Palmerston North, 4474, New Zealand.
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20
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Zhou T, Xue Y, Ren F, Dong Y. Antioxidant activity of xylooligosaccharides prepared fromThermotoga maritimausing recombinant enzyme cocktail of β-xylanase and α-glucuronidase. J Carbohydr Chem 2018. [DOI: 10.1080/07328303.2018.1455843] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- Tao Zhou
- Department of Food Science and Nutrition, GinLing College, Nanjing Normal University, Nanjing, PR China
| | - Yemin Xue
- Department of Food Science and Nutrition, GinLing College, Nanjing Normal University, Nanjing, PR China
| | - Fengjiao Ren
- Department of Food Science and Nutrition, GinLing College, Nanjing Normal University, Nanjing, PR China
| | - Yuanyuan Dong
- Department of Food Science and Nutrition, GinLing College, Nanjing Normal University, Nanjing, PR China
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21
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Ma R, Huang H, Bai Y, Luo H, Fan Y, Yao B. Insight into the cold adaptation and hemicellulose utilization of Cladosporium neopsychrotolerans from genome analysis and biochemical characterization. Sci Rep 2018; 8:6075. [PMID: 29666397 PMCID: PMC5904165 DOI: 10.1038/s41598-018-24443-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 03/20/2018] [Indexed: 11/30/2022] Open
Abstract
The occurrence of Cladosporium in cold ecosystems has been evidenced long before, and most of the knowledge about nutrient utilization of this genus is sporadic. An alpine soil isolate C. neopsychrotolerans SL-16, showing great cold tolerance and significant lignocellulose-degrading capability, was sequenced to form a 35.9 Mb genome that contains 13,456 predicted genes. Functional annotation on predicted genes revealed a wide array of proteins involved in the transport and metabolism of carbohydrate, protein and lipid. Large numbers of transmembrane proteins (967) and CAZymes (571) were identified, and those related to hemicellulose degradation was the most abundant. To undermine the hemicellulose (xyaln as the main component) utilization mechanism of SL-16, the mRNA levels of 23 xylanolytic enzymes were quantified, and representatives of three glycoside hydrolase families were functionally characterized. The enzymes showed similar neutral, cold active and thermolabile properties and synergistic action on xylan degradation (the synergy degree up to 15.32). Kinetic analysis and sequence and structure comparison with mesophilic and thermophilic homologues indicated that these cold-active enzymes employed different cold adaptation strategies to function well in cold environment. These similar and complementary advantages in cold adaptation and catalysis might explain the high efficiency of lignocellulose conversion observed in SL-16 under low temperatures.
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Affiliation(s)
- Rui Ma
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
- Biotechnology Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huoqing Huang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yingguo Bai
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huiying Luo
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yunliu Fan
- Biotechnology Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bin Yao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.
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22
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Lee BD, Apel WA, Sheridan PP, DeVeaux LC. Glycoside hydrolase gene transcription by Alicyclobacillus acidocaldarius during growth on wheat arabinoxylan and monosaccharides: a proposed xylan hydrolysis mechanism. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:110. [PMID: 29686728 PMCID: PMC5901876 DOI: 10.1186/s13068-018-1110-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 04/06/2018] [Indexed: 05/09/2023]
Abstract
BACKGROUND Metabolism of carbon bound in wheat arabinoxylan (WAX) polysaccharides by bacteria requires a number of glycoside hydrolases active toward different bonds between sugars and other molecules. Alicyclobacillus acidocaldarius is a Gram-positive thermoacidophilic bacterium capable of growth on a variety of mono-, di-, oligo-, and polysaccharides. Nineteen proposed glycoside hydrolases have been annotated in the A. acidocaldarius Type Strain ATCC27009/DSM 446 genome. Experiments were performed to understand the effect of monosaccharides on gene expression during growth on the polysaccharide, WAX. RESULTS Molecular analysis using high-density oligonucleotide microarrays was performed on A. acidocaldarius strain ATCC27009 when growing on WAX. When a culture growing exponentially at the expense of arabinoxylan saccharides was challenged with glucose or xylose, most glycoside hydrolases were downregulated. Interestingly, regulation was more intense when xylose was added to the culture than when glucose was added, showing a clear departure from classical carbon catabolite repression demonstrated by many Gram-positive bacteria. In silico analyses of the regulated glycoside hydrolases, along with the results from the microarray analyses, yielded a potential mechanism for arabinoxylan metabolism by A. acidocaldarius. Glycoside hydrolases expressed by this strain may have broad substrate specificity, and initial hydrolysis is catalyzed by an extracellular xylanase, while subsequent steps are likely performed inside the growing cell. CONCLUSIONS Glycoside hydrolases, for the most part, appear to be found in clusters, throughout the A. acidocaldarius genome. Not all of the glycoside hydrolase genes found at loci within these clusters were regulated during the experiment, indicating that a specific subset of the 19 glycoside hydrolase genes found in A. acidocaldarius were used during metabolism of WAX. While specific functions of the glycoside hydrolases were not tested as part of the research discussed, many of the glycoside hydrolases found in the A. acidocaldarius Type Strain appear to have a broader substrate range than that represented by the glycoside hydrolase family in which the enzymes were categorized.
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Affiliation(s)
- Brady D. Lee
- Biological Systems Department, Idaho National Laboratory, P. O. Box 1625, Idaho Falls, ID 83415 USA
- Department of Biological Sciences, Idaho State University, Campus Box 8007, Pocatello, ID 83209 USA
- Present Address: Pacific Northwest National Laboratory, Energy and Environment Directorate, Richland, WA USA
| | - William A. Apel
- Biological Systems Department, Idaho National Laboratory, P. O. Box 1625, Idaho Falls, ID 83415 USA
| | - Peter P. Sheridan
- Department of Biological Sciences, Idaho State University, Campus Box 8007, Pocatello, ID 83209 USA
| | - Linda C. DeVeaux
- Department of Biology, New Mexico Institute of Mining and Technology, 801 Leroy Pl, Socorro, NM 87801 USA
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Enzymatic Mechanism for Arabinan Degradation and Transport in the Thermophilic Bacterium Caldanaerobius polysaccharolyticus. Appl Environ Microbiol 2017; 83:AEM.00794-17. [PMID: 28710263 DOI: 10.1128/aem.00794-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/05/2017] [Indexed: 12/21/2022] Open
Abstract
The plant cell wall polysaccharide arabinan provides an important supply of arabinose, and unraveling arabinan-degrading strategies by microbes is important for understanding its use as a source of energy. Here, we explored the arabinan-degrading enzymes in the thermophilic bacterium Caldanaerobius polysaccharolyticus and identified a gene cluster encoding two glycoside hydrolase (GH) family 51 α-l-arabinofuranosidases (CpAbf51A, CpAbf51B), a GH43 endoarabinanase (CpAbn43A), a GH27 β-l-arabinopyranosidase (CpAbp27A), and two GH127 β-l-arabinofuranosidases (CpAbf127A, CpAbf127B). The genes were expressed as recombinant proteins, and the functions of the purified proteins were determined with para-nitrophenyl (pNP)-linked sugars and naturally occurring pectin structural elements as the substrates. The results demonstrated that CpAbn43A is an endoarabinanase while CpAbf51A and CpAbf51B are α-l-arabinofuranosidases that exhibit diverse substrate specificities, cleaving α-1,2, α-1,3, and α-1,5 linkages of purified arabinan-oligosaccharides. Furthermore, both CpAbf127A and CpAbf127B cleaved β-arabinofuranose residues in complex arabinan side chains, thus providing evidence of the function of this family of enzymes on such polysaccharides. The optimal temperatures of the enzymes ranged between 60°C and 75°C, and CpAbf43A and CpAbf51A worked synergistically to release arabinose from branched and debranched arabinan. Furthermore, the hydrolytic activity on branched arabinan oligosaccharides and degradation of pectic substrates by the endoarabinanase and l-arabinofuranosidases suggested a microbe equipped with diverse activities to degrade complex arabinan in the environment. Based on our functional analyses of the genes in the arabinan degradation cluster and the substrate-binding studies on a component of the cognate transporter system, we propose a model for arabinan degradation and transport by C. polysaccharolyticusIMPORTANCE Genomic DNA sequencing and bioinformatic analysis allowed the identification of a gene cluster encoding several proteins predicted to function in arabinan degradation and transport in C. polysaccharolyticus The analysis of the recombinant proteins yielded detailed insights into the putative arabinan metabolism of this thermophilic bacterium. The use of various branched arabinan oligosaccharides provided a detailed understanding of the substrate specificities of the enzymes and allowed assignment of two new GH127 polypeptides as β-l-arabinofuranosidases able to degrade pectic substrates, thus expanding our knowledge of this rare group of glycoside hydrolases. In addition, the enzymes showed synergistic effects for the degradation of arabinans at elevated temperatures. The enzymes characterized from the gene cluster are, therefore, of utility for arabinose production in both the biofuel and food industries.
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Bacterial diversity of the outflows of a Polichnitos (Lesvos, Greece) hot spring, laboratory studies of a Cyanobacterium sp. strain and potential medical applications. ANN MICROBIOL 2017. [DOI: 10.1007/s13213-017-1293-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Wefers D, Cavalcante JJ, Schendel RR, Deveryshetty J, Wang K, Wawrzak Z, Mackie RI, Koropatkin NM, Cann I. Biochemical and Structural Analyses of Two Cryptic Esterases in Bacteroides intestinalis and their Synergistic Activities with Cognate Xylanases. J Mol Biol 2017; 429:2509-2527. [DOI: 10.1016/j.jmb.2017.06.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/25/2017] [Accepted: 06/26/2017] [Indexed: 11/17/2022]
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Rhee MS, Sawhney N, Kim YS, Rhee HJ, Hurlbert JC, St John FJ, Nong G, Rice JD, Preston JF. GH115 α-glucuronidase and GH11 xylanase from Paenibacillus sp. JDR-2: potential roles in processing glucuronoxylans. Appl Microbiol Biotechnol 2016; 101:1465-1476. [PMID: 27766358 DOI: 10.1007/s00253-016-7899-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 09/13/2016] [Accepted: 09/25/2016] [Indexed: 01/26/2023]
Abstract
Paenibacillus sp. JDR-2 (Pjdr2) has been studied as a model for development of bacterial biocatalysts for efficient processing of xylans, methylglucuronoxylan, and methylglucuronoarabinoxylan, the predominant hemicellulosic polysaccharides found in dicots and monocots, respectively. Pjdr2 produces a cell-associated GH10 endoxylanase (Xyn10A1) that catalyzes depolymerization of xylans to xylobiose, xylotriose, and methylglucuronoxylotriose with methylglucuronate-linked α-1,2 to the nonreducing terminal xylose. A GH10/GH67 xylan utilization regulon includes genes encoding an extracellular cell-associated Xyn10A1 endoxylanase and an intracellular GH67 α-glucuronidase active on methylglucuronoxylotriose generated by Xyn10A1 but without activity on methylglucuronoxylotetraose generated by a GH11 endoxylanase. The sequenced genome of Pjdr2 contains three paralogous genes potentially encoding GH115 α-glucuronidases found in certain bacteria and fungi. One of these, Pjdr2_5977, shows enhanced expression during growth on xylans along with Pjdr2_4664 encoding a GH11 endoxylanase. Here, we show that Pjdr2_5977 encodes a GH115 α-glucuronidase, Agu115A, with maximal activity on the aldouronate methylglucuronoxylotetraose selectively generated by a GH11 endoxylanase Xyn11 encoded by Pjdr2_4664. Growth of Pjdr2 on this methylglucuronoxylotetraose supports a process for Xyn11-mediated extracellular depolymerization of methylglucuronoxylan and Agu115A-mediated intracellular deglycosylation as an alternative to the GH10/GH67 system previously defined in this bacterium. A recombinantly expressed enzyme encoded by the Pjdr2 agu115A gene catalyzes removal of 4-O-methylglucuronate residues α-1,2 linked to internal xylose residues in oligoxylosides generated by GH11 and GH30 xylanases and releases methylglucuronate from polymeric methylglucuronoxylan. The GH115 α-glucuronidase from Pjdr2 extends the discovery of this activity to members of the phylum Firmicutes and contributes to a novel system for bioprocessing hemicelluloses.
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Affiliation(s)
- Mun Su Rhee
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.,Xycrobe Therapeutics Inc., 3210 Merryfield Row, San Diego,, CA, 92121,, USA
| | - Neha Sawhney
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN, 37235,, USA
| | - Young Sik Kim
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA
| | - Hyun Jee Rhee
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.,Department of Materials Science and Engineering, Massachusetts Institute of Technology, 6-113, Cambridge, MA, 02139,, USA
| | - Jason C Hurlbert
- Department of Chemistry, Physics and Geology, Winthrop University, Rock Hill, SC, 29733, USA
| | - Franz J St John
- Forest Products Laboratory, United States Forest Service, The United States Department of Agriculture, Madison, Madison,, WI, 53726, USA
| | - Guang Nong
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA
| | - John D Rice
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA
| | - James F Preston
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA.
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Biochemical characterization of extra- and intracellular endoxylanse from thermophilic bacterium Caldicellulosiruptor kronotskyensis. Sci Rep 2016; 6:21672. [PMID: 26899227 PMCID: PMC4761950 DOI: 10.1038/srep21672] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/28/2016] [Indexed: 01/25/2023] Open
Abstract
Caldicellulosiruptor kronotskyensis grows on lignocellulosic biomass by the catalysis of intrinsic glycoside hydrolase, and has potential application for consolidated bioprocessing. In current study, two predicted extra- (Xyn10A) and intracellular (Xyn10B) xylanase from C. kronotskyensis were comparatively characterized. Xyn10A and Xyn10B share GH10 catalytic domain with similarity of 41%, while the former contains two tandem N-terminus CBM22s. Xyn10A showed higher hydrolytic capability than Xyn10B on both beechwood xylan (BWX) and oat spelt xylan (OSX). Truncation mutation experiments revealed the importance of CBMs for hydrolytic activity, substrate binding and thermostability of Xyn10A.While the quantity of CBM was not directly related to bind and thermostability. Although CBM was considered to be crucial for substrate binding, Xyn10B and Xyn10A as well as truncations performed similar binding affinity to insoluble substrate OSX. Analysis of point mutation revealed similar key residues, Glu493, Glu601 and Trp658 for Xyn10A and Glu139, Glu247 and Trp305 for Xyn10B. Both Xyn10A and Xyn10B exhibited hydrolytic activity on the mechanical pretreated corncob. After pre-digested by Xyn10A or Xyn10B, the micropores inthe the mechanical pretreated corncob were observed, which enhanced the accessibility for cellulase. Compared with corncob hydrolyzed with cellulase alone, enhanced hydrolytic performance of was observed after pre-digestion by Xyn10A or Xyn10B.
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Pandey S, Modak A, Phale PS, Bhaumik P. High Resolution Structures of Periplasmic Glucose-binding Protein of Pseudomonas putida CSV86 Reveal Structural Basis of Its Substrate Specificity. J Biol Chem 2016; 291:7844-57. [PMID: 26861882 DOI: 10.1074/jbc.m115.697268] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Indexed: 01/31/2023] Open
Abstract
Periplasmic substrate-binding proteins (SBPs) bind to the specific ligand with high affinity and mediate their transport into the cytoplasm via the cognate inner membrane ATP-binding cassette proteins. Because of low sequence identities, understanding the structural basis of substrate recognition by SBPs has remained very challenging. There are several structures available for the ligand-bound sugar SBPs, but very few unliganded structures are reported. No structural data are available for sugar SBPs fromPseudomonassp. to date. This study reports the first high resolution crystal structures of periplasmic glucose-binding protein fromPseudomonas putidaCSV86 (ppGBP) in unliganded form (2.5 Å) and complexed with glucose (1.25 Å) and galactose (1.8 Å). Asymmetric domain closure of ppGBP was observed upon substrate binding. The ppGBP was found to have an affinity of ∼ 0.3 μmfor glucose. The structural analysis showed that the sugars are bound to the protein mainly by hydrogen bonds, and the loss of two strong hydrogen bonds between ppGBP and galactose compared with glucose may be responsible for lowering its affinity toward galactose. The higher stability of ppGBP-glucose complex was also indicated by an 8 °C increase in the melting temperature compared with unliganded form and ppGBP-galactose complex. ppGBP binds to monosaccharide, but the structural features revealed it to have an oligosaccharide-binding protein fold, indicating that during evolution the sugar binding pocket may have undergone structural modulation to accommodate monosaccharide only.
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Affiliation(s)
- Suman Pandey
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Arnab Modak
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Prashant S Phale
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Prasenjit Bhaumik
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Conway JM, Pierce WS, Le JH, Harper GW, Wright JH, Tucker AL, Zurawski JV, Lee LL, Blumer-Schuette SE, Kelly RM. Multidomain, Surface Layer-associated Glycoside Hydrolases Contribute to Plant Polysaccharide Degradation by Caldicellulosiruptor Species. J Biol Chem 2016; 291:6732-47. [PMID: 26814128 DOI: 10.1074/jbc.m115.707810] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Indexed: 01/08/2023] Open
Abstract
The genome of the extremely thermophilic bacterium Caldicellulosiruptor kronotskyensisencodes 19 surface layer (S-layer) homology (SLH) domain-containing proteins, the most in any Caldicellulosiruptorspecies genome sequenced to date. These SLH proteins include five glycoside hydrolases (GHs) and one polysaccharide lyase, the genes for which were transcribed at high levels during growth on plant biomass. The largest GH identified so far in this genus, Calkro_0111 (2,435 amino acids), is completely unique toC. kronotskyensisand contains SLH domains. Calkro_0111 was produced recombinantly inEscherichia colias two pieces, containing the GH16 and GH55 domains, respectively, as well as putative binding and spacer domains. These displayed endo- and exoglucanase activity on the β-1,3-1,6-glucan laminarin. A series of additional truncation mutants of Calkro_0111 revealed the essential architectural features required for catalytic function. Calkro_0402, another of the SLH domain GHs inC. kronotskyensis, when produced inE. coli, was active on a variety of xylans and β-glucans. Unlike Calkro_0111, Calkro_0402 is highly conserved in the genus Caldicellulosiruptorand among other biomass-degrading Firmicutes but missing from Caldicellulosiruptor bescii As such, the gene encoding Calkro_0402 was inserted into the C. besciigenome, creating a mutant strain with its S-layer extensively decorated with Calkro_0402. This strain consequently degraded xylans more extensively than wild-typeC. bescii The results here provide new insights into the architecture and role of SLH domain GHs and demonstrate that hemicellulose degradation can be enhanced through non-native SLH domain GHs engineered into the genomes of Caldicellulosiruptorspecies.
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Affiliation(s)
- Jonathan M Conway
- From the Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695
| | - William S Pierce
- From the Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695
| | - Jaycee H Le
- From the Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695
| | - George W Harper
- From the Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695
| | - John H Wright
- From the Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695
| | - Allyson L Tucker
- From the Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695
| | - Jeffrey V Zurawski
- From the Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695
| | - Laura L Lee
- From the Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695
| | - Sara E Blumer-Schuette
- From the Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695
| | - Robert M Kelly
- From the Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695
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Cobucci-Ponzano B, Strazzulli A, Iacono R, Masturzo G, Giglio R, Rossi M, Moracci M. Novel thermophilic hemicellulases for the conversion of lignocellulose for second generation biorefineries. Enzyme Microb Technol 2015. [PMID: 26215346 DOI: 10.1016/j.enzmictec.2015.06.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The biotransformation of lignocellulose biomasses into fermentable sugars is a very complex procedure including, as one of the most critical steps, the (hemi) cellulose hydrolysis by specific enzymatic cocktails. We explored here, the potential of stable glycoside hydrolases from thermophilic organisms, so far not used in commercial enzymatic preparations, for the conversion of glucuronoxylan, the major hemicellulose of several energy crops. Searches in the genomes of thermophilic bacteria led to the identification, efficient production, and detailed characterization of novel xylanase and α-glucuronidase from Alicyclobacillus acidocaldarius (GH10-XA and GH67-GA, respectively) and a α-glucuronidase from Caldicellulosiruptor saccharolyticus (GH67-GC). Remarkably, GH10-XA, if compared to other thermophilic xylanases from this family, coupled good specificity on beechwood xylan and the best stability at 65 °C (3.5 days). In addition, GH67-GC was the most stable α-glucuronidases from this family and the first able to hydrolyse both aldouronic acid and aryl-α-glucuronic acid substrates. These enzymes, led to the very efficient hydrolysis of beechwood xylan by using 7- to 9-fold less protein (concentrations <0.3 μM) and in much less reaction time (2h vs 12h) if compared to other known biotransformations catalyzed by thermophilic enzymes. In addition, remarkably, together with a thermophilic β-xylosidase, they catalyzed the production of xylose from the smart cooking pre-treated biomass of one of the most promising energy crops for second generation biorefineries. We demonstrated that search by the CAZy Data Bank of currently available genomes and detailed enzymatic characterization of recombinant enzymes allow the identification of glycoside hydrolases with novel and interesting properties and applications.
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Affiliation(s)
- Beatrice Cobucci-Ponzano
- Institute of Biosciences and Bioresources, National Research Council of Italy, Via P. Castellino 111, 80131 Naples, Italy.
| | - Andrea Strazzulli
- Institute of Biosciences and Bioresources, National Research Council of Italy, Via P. Castellino 111, 80131 Naples, Italy.
| | - Roberta Iacono
- Institute of Biosciences and Bioresources, National Research Council of Italy, Via P. Castellino 111, 80131 Naples, Italy.
| | - Giuseppe Masturzo
- Institute of Biosciences and Bioresources, National Research Council of Italy, Via P. Castellino 111, 80131 Naples, Italy.
| | - Rosa Giglio
- Institute of Biosciences and Bioresources, National Research Council of Italy, Via P. Castellino 111, 80131 Naples, Italy.
| | - Mosè Rossi
- Institute of Biosciences and Bioresources, National Research Council of Italy, Via P. Castellino 111, 80131 Naples, Italy.
| | - Marco Moracci
- Institute of Biosciences and Bioresources, National Research Council of Italy, Via P. Castellino 111, 80131 Naples, Italy.
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Urbieta MS, Donati ER, Chan KG, Shahar S, Sin LL, Goh KM. Thermophiles in the genomic era: Biodiversity, science, and applications. Biotechnol Adv 2015; 33:633-47. [PMID: 25911946 DOI: 10.1016/j.biotechadv.2015.04.007] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 12/18/2014] [Accepted: 04/14/2015] [Indexed: 01/30/2023]
Abstract
Thermophiles and hyperthermophiles are present in various regions of the Earth, including volcanic environments, hot springs, mud pots, fumaroles, geysers, coastal thermal springs, and even deep-sea hydrothermal vents. They are also found in man-made environments, such as heated compost facilities, reactors, and spray dryers. Thermophiles, hyperthermophiles, and their bioproducts facilitate various industrial, agricultural, and medicinal applications and offer potential solutions to environmental damages and the demand for biofuels. Intensified efforts to sequence the entire genome of hyperthermophiles and thermophiles are increasing rapidly, as evidenced by the fact that over 120 complete genome sequences of the hyperthermophiles Aquificae, Thermotogae, Crenarchaeota, and Euryarchaeota are now available. In this review, we summarise the major current applications of thermophiles and thermozymes. In addition, emphasis is placed on recent progress in understanding the biodiversity, genomes, transcriptomes, metagenomes, and single-cell sequencing of thermophiles in the genomic era.
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Affiliation(s)
- M Sofía Urbieta
- CINDEFI (CCT La Plata-CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calle 47 y 115, 1900 La Plata, Argentina
| | - Edgardo R Donati
- CINDEFI (CCT La Plata-CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calle 47 y 115, 1900 La Plata, Argentina
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Saleha Shahar
- Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Malaysia
| | - Lee Li Sin
- Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Malaysia
| | - Kian Mau Goh
- Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Malaysia.
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Schmidt D, Schuhmacher F, Geissner A, Seeberger PH, Pfrengle F. Automated Synthesis of Arabinoxylan-Oligosaccharides Enables Characterization of Antibodies that Recognize Plant Cell Wall Glycans. Chemistry 2015; 21:5709-13. [DOI: 10.1002/chem.201500065] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Indexed: 11/06/2022]
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Cockburn DW, Orlovsky NI, Foley MH, Kwiatkowski KJ, Bahr CM, Maynard M, Demeler B, Koropatkin NM. Molecular details of a starch utilization pathway in the human gut symbiont Eubacterium rectale. Mol Microbiol 2015; 95:209-30. [PMID: 25388295 PMCID: PMC4437465 DOI: 10.1111/mmi.12859] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2014] [Indexed: 01/07/2023]
Abstract
Eubacterium rectale is a prominent human gut symbiont yet little is known about the molecular strategies this bacterium has developed to acquire nutrients within the competitive gut ecosystem. Starch is one of the most abundant glycans in the human diet, and E. rectale increases in vivo when the host consumes a diet rich in resistant starch, although it is not a primary degrader of this glycan. Here we present the results of a quantitative proteomics study in which we identify two glycoside hydrolase 13 family enzymes, and three ABC transporter solute-binding proteins that are abundant during growth on starch and, we hypothesize, work together at the cell surface to degrade starch and capture the released maltooligosaccharides. EUR_21100 is a multidomain cell wall anchored amylase that preferentially targets starch polysaccharides, liberating maltotetraose, whereas the membrane-associated maltogenic amylase EUR_01860 breaks down maltooligosaccharides longer than maltotriose. The three solute-binding proteins display a range of glycan-binding specificities that ensure the capture of glucose through maltoheptaose and some α1,6-branched glycans. Taken together, we describe a pathway for starch utilization by E. rectale DSM 17629 that may be conserved among other starch-degrading Clostridium cluster XIVa organisms in the human gut.
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Affiliation(s)
- Darrell W. Cockburn
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Nicole I. Orlovsky
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Matthew H. Foley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Kurt J. Kwiatkowski
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Constance M. Bahr
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Mallory Maynard
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Borries Demeler
- Department of Biochemistry, The University of Texas Health Science Center, San Antonio, TX 78229
| | - Nicole M. Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
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Peng X, Qiao W, Mi S, Jia X, Su H, Han Y. Characterization of hemicellulase and cellulase from the extremely thermophilic bacterium Caldicellulosiruptor owensensis and their potential application for bioconversion of lignocellulosic biomass without pretreatment. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:131. [PMID: 26322125 PMCID: PMC4552416 DOI: 10.1186/s13068-015-0313-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 08/13/2015] [Indexed: 05/08/2023]
Abstract
BACKGROUND Pretreatment is currently the common approach for improving the efficiency of enzymatic hydrolysis on lignocellulose. However, the pretreatment process is expensive and will produce inhibitors such as furan derivatives and phenol derivatives. If the lignocellulosic biomass can efficiently be saccharified by enzymolysis without pretreatment, the bioconversion process would be simplified. The genus Caldicellulosiruptor, an obligatory anaerobic and extreme thermophile can produce a diverse set of glycoside hydrolases (GHs) for deconstruction of lignocellulosic biomass. It gives potential opportunities for improving the efficiency of converting native lignocellulosic biomass to fermentable sugars. RESULTS Both of the extracellular (extra-) and intracellular (intra-) enzymes of C. owensensis cultivated on corncob xylan or xylose had cellulase (including endoglucanase, cellobiohydrolase and β-glucosidase) and hemicellulase (including xylanase, xylosidase, arabinofuranosidase and acetyl xylan esterase) activities. The enzymes of C. owensensis had high ability for degrading hemicellulose of native corn stover and corncob with the conversion rates of xylan 16.7 % and araban 60.0 %. Moreover, they had remarkable synergetic function with the commercial enzyme cocktail Cellic CTec2 (Novoyzmes). When the native corn stover and corncob were respectively, sequentially hydrolyzed by the extra-enzymes of C. owensensis and CTec2, the glucan conversion rates were 31.2 and 37.9 %,which were 1.7- and 1.9-fold of each control (hydrolyzed by CTec2 alone), whereas the glucan conversion rates of the steam-exploded corn stover and corncob hydrolyzed by CTec2 alone on the same loading rate were 38.2 and 39.6 %, respectively. These results show that hydrolysis by the extra-enzyme of C. owensensis made almost the same contribution as steam-exploded pretreatment on degradation of native lignocellulosic biomass. A new process for saccharification of lignocellulosic biomass by sequential hydrolysis is demonstrated in the present research, namely hyperthermal enzymolysis (70-80 °C) by enzymes of C. owensensis followed with mesothermal enzymolysis (50-55 °C) by commercial cellulase. This process has the advantages of no sugar loss, few inhibitors generation and consolidated with sterilization. CONCLUSIONS The enzymes of C. owensensis demonstrated an enhanced ability to degrade the hemicellulose of native lignocellulose. The pretreatment and detoxification steps may be removed from the bioconversion process of the lignocellulosic biomass by using the enzymes from C. owensensis.
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Affiliation(s)
- Xiaowei Peng
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Weibo Qiao
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Shuofu Mi
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Xiaojing Jia
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Hong Su
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Yejun Han
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
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Chekan JR, Kwon IH, Agarwal V, Dodd D, Revindran V, Mackie RI, Cann I, Nair SK. Structural and biochemical basis for mannan utilization by Caldanaerobius polysaccharolyticus strain ATCC BAA-17. J Biol Chem 2014; 289:34965-77. [PMID: 25342756 DOI: 10.1074/jbc.m114.579904] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Hemicelluloses, the polysaccharide component of plant cell walls, represent one of the most abundant biopolymers in nature. The most common hemicellulosic constituents of softwoods, such as conifers and cycads, are mannans consisting of a 1,4-linked β-mannopyranosyl main chain with branch decorations. Efforts toward the utilization of hemicellulose for bioconversion into cellulosic biofuels have resulted in the identification of several families of glycoside hydrolases that can degrade mannan. However, effective biofermentation of manno-oligosaccharides is limited by a lack of appropriate uptake route in ethanologenic organisms. Here, we used transcriptome sequencing to gain insights into mannan degradation by the thermophilic anaerobic bacterium Caldanaerobius polysaccharolyticus. The most highly up-regulated genes during mannan fermentation occur in a cluster containing several genes encoding enzymes for efficient mannan hydrolysis as well as a solute-binding protein (CpMnBP1) that exhibits specificity for short mannose polymers but exhibited the flexibility to accommodate branched polysaccharide decorations. Co-crystal structures of CpMnBP1 in complex with mannobiose (1.4-Å resolution) and mannotriose (2.2-Å resolution) revealed the molecular rationale for chain length and oligosaccharide specificity. Calorimetric analysis of several active site variants confirmed the roles of residues critical to the function of CpMnBP1. This work represents the first biochemical characterization of a mannose-specific solute-binding protein and provides a framework for engineering mannan utilization capabilities for microbial fermentation.
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Affiliation(s)
| | | | | | - Dylan Dodd
- Institute for Genomic Biology, Energy Biosciences Institute, University of Illinois, Urbana, Illinois 61801 Microbiology
| | - Vanessa Revindran
- Institute for Genomic Biology, Energy Biosciences Institute, University of Illinois, Urbana, Illinois 61801
| | - Roderick I Mackie
- Institute for Genomic Biology, Animal Sciences, and Energy Biosciences Institute, University of Illinois, Urbana, Illinois 61801
| | - Isaac Cann
- Institute for Genomic Biology, Animal Sciences, and Energy Biosciences Institute, University of Illinois, Urbana, Illinois 61801 Microbiology,
| | - Satish K Nair
- From the Departments of Biochemistry, Institute for Genomic Biology, Center for Biophysics and Computational Biology, and
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Jia X, Mi S, Wang J, Qiao W, Peng X, Han Y. Insight into glycoside hydrolases for debranched xylan degradation from extremely thermophilic bacterium Caldicellulosiruptor lactoaceticus. PLoS One 2014; 9:e106482. [PMID: 25184498 PMCID: PMC4153629 DOI: 10.1371/journal.pone.0106482] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 08/05/2014] [Indexed: 11/18/2022] Open
Abstract
Caldicellulosiruptor lactoaceticus 6A, an anaerobic and extremely thermophilic bacterium, uses natural xylan as carbon source. The encoded genes of C. lactoaceticus 6A for glycoside hydrolase (GH) provide a platform for xylan degradation. The GH family 10 xylanase (Xyn10A) and GH67 α-glucuronidase (Agu67A) from C. lactoaceticus 6A were heterologously expressed, purified and characterized. Both Xyn10A and Agu67A are predicted as intracellular enzymes as no signal peptides identified. Xyn10A and Agu67A had molecular weight of 47.0 kDa and 80.0 kDa respectively as determined by SDS-PAGE, while both appeared as homodimer when analyzed by gel filtration. Xyn10A displayed the highest activity at 80 °C and pH 6.5, as 75 °C and pH 6.5 for Agu67A. Xyn10A had good stability at 75 °C, 80 °C, and pH 4.5-8.5, respectively, and was sensitive to various metal ions and reagents. Xyn10A possessed hydrolytic activity towards xylo-oligosaccharides (XOs) and beechwood xylan. At optimum conditions, the specific activity of Xyn10A was 44.6 IU/mg with beechwood xylan as substrate, and liberated branched XOs, xylobiose, and xylose. Agu67A was active on branched XOs with methyl-glucuronic acids (MeGlcA) sub-chains, and primarily generated XOs equivalents and MeGlcA. The specific activity of Agu67A was 1.3 IU/mg with aldobiouronic acid as substrate. The synergistic action of Xyn10A and Agu67A was observed with MeGlcA branched XOs and xylan as substrates, both backbone and branched chain of substrates were degraded, and liberated xylose, xylobiose, and MeGlcA. The synergism of Xyn10A and Agu67A provided not only a thermophilic method for natural xylan degradation, but also insight into the mechanisms for xylan utilization of C. lactoaceticus.
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Affiliation(s)
- Xiaojing Jia
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Shuofu Mi
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Jinzhi Wang
- Institute of Agro-food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Weibo Qiao
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- College of Biosciences and Biotechnology, Shenyang Agricultural University, Shenyang, China
| | - Xiaowei Peng
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Yejun Han
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
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Biochemical characterization of two thermostable xylanolytic enzymes encoded by a gene cluster of Caldicellulosiruptor owensensis. PLoS One 2014; 9:e105264. [PMID: 25127169 PMCID: PMC4134300 DOI: 10.1371/journal.pone.0105264] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 07/19/2014] [Indexed: 02/04/2023] Open
Abstract
The xylanolytic extremely thermophilic bacterium Caldicellulosiruptor owensensis provides a promising platform for xylan utilization. In the present study, two novel xylanolytic enzymes, GH10 endo-β-1,4-xylanase (Coxyn A) and GH39 β-1,4-xylosidase (Coxyl A) encoded in one gene cluster of C.owensensis were heterogeneously expressed and biochemically characterized. The optimum temperature of the two xylanlytic enzymes was 75°C, and the respective optimum pH for Coxyn A and Coxyl A was 7.0 and 5.0. The difference of Coxyn A and Coxyl A in solution was existing as monomer and homodimer respectively, it was also observed in predicted secondary structure. Under optimum condition, the catalytic efficiency (kcat/Km) of Coxyn A was 366 mg ml−1 s−1 on beechwood xylan, and the catalytic efficiency (kcat/Km) of Coxyl A was 2253 mM−1 s−1 on pNP-β-D-xylopyranoside. Coxyn A degraded xylan to oligosaccharides, which were converted to monomer by Coxyl A. The two intracellular enzymes might be responsible for xylooligosaccharides utilization in C.owensensis, also provide a potential way for xylan degradation in vitro.
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Abstract
The term "extremophile" was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of "extreme" environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally "hot environments" on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong to the Archaea has definitely made this area of investigation more exciting. Particularly fascinating are their structural and physiological features allowing them to withstand extremely selective environmental conditions. These properties are often due to specific biomolecules (DNA, lipids, enzymes, osmolites, etc.) that have been studied for years as novel sources for biotechnological applications. In some cases (DNA-polymerase, thermostable enzymes), the search and applications successful exceeded preliminary expectations, but certainly further exploitations are still needed.
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Ejby M, Fredslund F, Vujicic-Zagar A, Svensson B, Slotboom DJ, Abou Hachem M. Structural basis for arabinoxylo-oligosaccharide capture by the probiotic Bifidobacterium animalis subsp. lactis Bl-04. Mol Microbiol 2013; 90:1100-12. [PMID: 24279727 DOI: 10.1111/mmi.12419] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2013] [Indexed: 11/27/2022]
Abstract
Glycan utilization plays a key role in modulating the composition of the gut microbiota, but molecular insight into oligosaccharide uptake by this microbial community is lacking. Arabinoxylo-oligosaccharides (AXOS) are abundant in the diet, and are selectively fermented by probiotic bifidobacteria in the colon. Here we show how selectivity for AXOS uptake is established by the probiotic strain Bifidobacterium animalis subsp. lactis Bl-04. The binding protein BlAXBP, which is associated with an ATP-binding cassette (ABC) transporter that mediates the uptake of AXOS, displays an exceptionally broad specificity for arabinosyl-decorated and undecorated xylo-oligosaccharides, with preference for tri- and tetra-saccharides. Crystal structures of BlAXBP in complex with four different ligands revealed the basis for this versatility. Uniquely, the protein was able to recognize oligosaccharides in two opposite orientations, which facilitates the optimization of interactions with the various ligands. Broad substrate specificity was further enhanced by a spacious binding pocket accommodating decorations at different mainchain positions and conformational flexibility of a lid-like loop. Phylogenetic and genetic analyses show that BlAXBP is highly conserved within Bifidobacterium, but is lacking in other gut microbiota members. These data indicate niche adaptation within Bifidobacterium and highlight the metabolic syntrophy (cross-feeding) among the gut microbiota.
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Affiliation(s)
- Morten Ejby
- Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800, Kgs. Lyngby, Denmark
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Yokoyama H, Yamashita T, Horikoshi N, Kurumizaka H, Kagawa W. Crystallization and preliminary X-ray diffraction analysis of the secreted protein Athe_0614 from Caldicellulosiruptor bescii. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:438-40. [PMID: 23545654 PMCID: PMC3614173 DOI: 10.1107/s174430911300554x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 02/26/2013] [Indexed: 11/10/2022]
Abstract
The Athe_0614 protein is a component of the extracellular proteins secreted by the anaerobic, extremely thermophilic and cellulolytic bacterium Caldicellulosiruptor bescii. The recombinant protein was expressed in Escherichia coli, purified to near-homogeneity and crystallized using polyethylene glycol 2000 monomethyl ether as a precipitant. The crystals belonged to the monoclinic space group P2(1), with unit-cell parameters a = 48.4, b = 42.2, c = 97.8 Å, β = 96.1°, and diffracted to 2.7 Å resolution using synchrotron radiation.
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Affiliation(s)
- Hiroshi Yokoyama
- Animal Waste Management and Environment Division, National Institute of Livestock and Grassland Science, 2 Ikenodai, Tsukuba, Ibaraki 305-0901, Japan
| | - Takahiro Yamashita
- Animal Waste Management and Environment Division, National Institute of Livestock and Grassland Science, 2 Ikenodai, Tsukuba, Ibaraki 305-0901, Japan
| | - Naoki Horikoshi
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Wataru Kagawa
- Program in Chemistry and Life Science, Department of Interdisciplinary Science and Engineering, School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino-shi, Tokyo 191-8506, Japan
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