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Liu M, Wei G, Lai Q, Huang Z, Li M, Shao Z. Genomic and metabolic insights into the first host-associated isolate of Psychrilyobacter. Microbiol Spectr 2023; 11:e0399022. [PMID: 37754757 PMCID: PMC10580919 DOI: 10.1128/spectrum.03990-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 08/11/2023] [Indexed: 09/28/2023] Open
Abstract
Although gut bacteria are vital to their hosts, few studies have focused on marine animals. Psychrilyobacter is frequently related to various marine animals, but its interaction with host remains unknown due to the lack of host-associated isolate or genomic information. Here, we combined cultivation-independent and cultivation-dependent methods to uncover the potential roles of Psychrilyobacter in the host abalone. The high-throughput sequencing and literature compiling results indicated that Psychrilyobacter is widely distributed in marine and terrestrial ecosystems with both host-associated and free-living lifestyles, but with a strong niche preference in the guts of marine invertebrates, especially abalone. By in vitro enrichment that mimicked the gut inner environment, the first host-related pure culture of Psychrilyobacter was isolated from the abalone intestine. Phylogenetic, physiological, and biochemical characterizations suggested that it represents a novel species named Psychrilyobacter haliotis B1. Carbohydrate utilization experiments and genomic evidence indicated that B1 can utilize diverse host-food-related monosaccharides and disaccharides but not polysaccharides, implying its potential role in the downstream fermentation instead of the upstream food degradation in the gut. Particularly, this strain showed potential to colonize the gut and benefit the host via different strategies, such as the short-chain fatty acids generation by fermenting peptides and/or amino acids, and the putative production of diverse vitamins and antibiotics to support the host growth and antipathogenicity. To our knowledge, strain B1 represents the first host-related pure culture of Psychrilyobacter; genomic and metabolic evidence showed some beneficial characteristics of the dominant gut anaerobe to the host. IMPORTANCE Psychrilyobacter is a globally distributed bacterial genus and with an inhabiting preference for guts of marine invertebrates. Due to the difficulty of cultivation and the limited genomic information, its role in host remains largely unknown. We isolated the first host-associated Psychrilyobacter species from abalone gut and uncovered its functional potential to the host through different mechanisms. Our findings provide some insights into the understanding of host-microbe interactions on a core taxon with the marine invertebrates, and the isolate may have an application potential in the protection of marine animals.
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Affiliation(s)
- Meijia Liu
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources of the PR China; State Key Laboratory Breeding Base of Marine Genetic Resources; Fujian Key Laboratory of Marine Genetic Resources, Xiamen, China
| | - Guangshan Wei
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources of the PR China; State Key Laboratory Breeding Base of Marine Genetic Resources; Fujian Key Laboratory of Marine Genetic Resources, Xiamen, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Marine Sciences, Sun Yat-Sen University, Zhuhai, China
| | - Qiliang Lai
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources of the PR China; State Key Laboratory Breeding Base of Marine Genetic Resources; Fujian Key Laboratory of Marine Genetic Resources, Xiamen, China
| | - Zhaobin Huang
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources of the PR China; State Key Laboratory Breeding Base of Marine Genetic Resources; Fujian Key Laboratory of Marine Genetic Resources, Xiamen, China
| | - Min Li
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Zongze Shao
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources of the PR China; State Key Laboratory Breeding Base of Marine Genetic Resources; Fujian Key Laboratory of Marine Genetic Resources, Xiamen, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Marine Sciences, Sun Yat-Sen University, Zhuhai, China
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Cao S, Li L, Li Q, Jiang L, Zhu B, Yao Z. A novel alginate lyase and its domain functions for the preparation of unsaturated monosaccharides. Appl Microbiol Biotechnol 2023; 107:1737-1749. [PMID: 36795142 DOI: 10.1007/s00253-023-12424-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 12/30/2022] [Accepted: 02/01/2023] [Indexed: 02/17/2023]
Abstract
Brown algae are considered promising crops for the production of sustainable biofuels. However, the commercial application has been limited by lack of efficient methods for converting alginate into fermentable sugars. Herein, we cloned and characterized a novel alginate lyase AlyPL17 from Pedobacter hainanensis NJ-02. It possessed outstanding catalytic efficiency toward polymannuronic acid (polyM), polyguluronic acid (polyG), and alginate sodium, with kcat of 39.42 ± 1.9 s-1, 32.53 ± 0.88 s-1, and 38.30 ± 2.12 s-1, respectively. AlyPL17 showed maximum activity at 45 °C and pH 9.0. The domain truncation did not change the optimal temperature and optimal pH, but greatly reduced the activity. In addition, AlyPL17 degrades alginate through the cooperative action of two structural domains in an exolytic mode. The minimal degradation substrate of AlyPL17 is a disaccharide. Furthermore, AlyPL17 and AlyPL6 can synergistically degrade alginate to prepare unsaturated monosaccharides that can be converted to 4-deoxy-L-erythron-5-hexoseuloseuronate acid (DEH). DEH is reduced to KDG by DEH reductase (Sdr), which enters the Entner-Doudoroff (ED) pathway as a common metabolite and is converted to bioethanol. KEY POINTS: • Biochemical characterization of alginate lyase from Pedobacter hainanensis NJ-02 and its truncated form. • Degradation patterns of AlyPL17 and the role of its domains in product distribution and mode of action. • Potential of synergistic degradation system for efficient preparation of unsaturated monosaccharides.
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Affiliation(s)
- Shengsheng Cao
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, China
| | - Li Li
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, China
| | - Qian Li
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, China
| | - Ling Jiang
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, China
| | - Benwei Zhu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, China.
| | - Zhong Yao
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, China
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Mrudulakumari Vasudevan U, Lee OK, Lee EY. Alginate derived functional oligosaccharides: Recent developments, barriers, and future outlooks. Carbohydr Polym 2021; 267:118158. [PMID: 34119132 DOI: 10.1016/j.carbpol.2021.118158] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/14/2021] [Accepted: 04/14/2021] [Indexed: 02/07/2023]
Abstract
Alginate is a biopolymer used extensively in the food, pharmaceutical, and chemical industries. Alginate oligosaccharides (AOS) derived from alginate exhibit superior biological activities and therapeutic potential. Alginate lyases with characteristic substrate specificity can facilitate the production of a broad array of AOS with precise structure and functionality. By adopting innovative analytical tools in conjunction with focused clinical studies, the structure-bioactivity relationship of a number of AOS has been brought to light. This review covers fundamental aspects and recent developments in AOS research. Enzymatic and microbial processes involved in AOS production from brown algae and sequential steps involved in AOS structure elucidation are outlined. Biological mechanisms underlying the health benefits of AOS and their potential industrial and therapeutic applications are elaborated. Withal, various challenges in AOS research are traced out, and future directions, specifically on recombinant systems for AOS preparation, are delineated to further widen the horizon of these exceptional oligosaccharides.
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Affiliation(s)
- Ushasree Mrudulakumari Vasudevan
- Department of Chemical Engineering (Integrated Engineering), Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea
| | - Ok Kyung Lee
- Department of Chemical Engineering (Integrated Engineering), Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering (Integrated Engineering), Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea.
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Alginate Degradation: Insights Obtained through Characterization of a Thermophilic Exolytic Alginate Lyase. Appl Environ Microbiol 2021; 87:AEM.02399-20. [PMID: 33397696 DOI: 10.1128/aem.02399-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/19/2020] [Indexed: 01/07/2023] Open
Abstract
Enzymatic depolymerization of seaweed polysaccharides is gaining interest for the production of functional oligosaccharides and fermentable sugars. Herein, we describe a thermostable alginate lyase that belongs to polysaccharide lyase family 17 (PL17) and was derived from an Arctic Mid-Ocean Ridge (AMOR) metagenomics data set. This enzyme, AMOR_PL17A, is a thermostable exolytic oligoalginate lyase (EC 4.2.2.26), which can degrade alginate, poly-β-d-mannuronate, and poly-α-l-guluronate within a broad range of pHs, temperatures, and salinity conditions. Site-directed mutagenesis showed that tyrosine Y251, previously suggested to act as a catalytic acid, indeed is essential for catalysis, whereas mutation of tyrosine Y446, previously proposed to act as a catalytic base, did not affect enzyme activity. The observed reaction products are protonated and deprotonated forms of the 4,5-unsaturated uronic acid monomer, Δ, two hydrates of DEH (4-deoxy-l-erythro-5-hexulosuronate), which are formed after ring opening, and, finally, two epimers of a 5-member hemiketal called 4-deoxy-d-manno-hexulofuranosidonate (DHF), formed through intramolecular cyclization of hydrated DEH. The detection and nuclear magnetic resonance (NMR) assignment of these hemiketals refine our current understanding of alginate degradation.IMPORTANCE The potential markets for seaweed-derived products and seaweed processing technologies are growing, yet commercial enzyme cocktails for complete conversion of seaweed to fermentable sugars are not available. Such an enzyme cocktail would require the catalytic properties of a variety of different enzymes, where fucoidanases, laminarinases, and cellulases together with endo- and exo-acting alginate lyases would be the key enzymes. Here, we present an exo-acting alginate lyase that efficiently produces monomeric sugars from alginate. Since it is only the second characterized exo-acting alginate lyase capable of degrading alginate at a high industrially relevant temperature (≥60°C), this enzyme may be of great biotechnological and industrial interest. In addition, in-depth NMR-based structural elucidation revealed previously undescribed rearrangement products of the unsaturated monomeric sugars generated from exo-acting lyases. The insight provided by the NMR assignment of these products facilitates future assessment of product formation by alginate lyases.
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Dharani SR, Srinivasan R, Sarath R, Ramya M. Recent progress on engineering microbial alginate lyases towards their versatile role in biotechnological applications. Folia Microbiol (Praha) 2020; 65:937-954. [DOI: 10.1007/s12223-020-00802-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 05/16/2020] [Indexed: 11/30/2022]
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Cheng D, Liu Z, Jiang C, Li L, Xue C, Mao X. Biochemical characterization and degradation pattern analysis of a novel PL-6 alginate lyase from Streptomyces coelicolor A3(2). Food Chem 2020; 323:126852. [PMID: 32334319 DOI: 10.1016/j.foodchem.2020.126852] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/26/2020] [Accepted: 04/17/2020] [Indexed: 11/30/2022]
Abstract
Alginate is the main component of brown algae which contributes to a huge biomass. The alginate oligosaccharides (AOs) have been widely used in food, cosmetic and pharmaceutical industries due to their various physiological activities. In this study, we expressed and characterized a novel PL-6 alginate lyase, named OUC-ScCD6. The results indicated that OUC-ScCD6 showed highest activity at 50 °C and pH 9.0. OUC-ScCD6 prefers to degrade poly M blocks and could digest poly G blocks as well. Endolytic action mode towards polysaccharides contributes to the creation of AOs with the degrees of polymerization 2-6. Degradation towards saturated oligosaccharides showed that saturated trisaccharides (M3 and G3) were minimum identifiable substrates. Furthermore, OUC-ScCD6 shows an even-numbered glycosidic bonds preference from non-reducing end which provided clearer insights into the substrate recognition and action mode of PL-6 family alginate lyases.
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Affiliation(s)
- Danyang Cheng
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Zhen Liu
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Chengcheng Jiang
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Laihao Li
- Key Laboratory of Aquatic Product Processing, Ministry of Agriculture, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou 510300, China
| | - Changhu Xue
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Xiangzhao Mao
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
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Belik AA, Silchenko AS, Kusaykin MI, Zvyagintseva TN, Ermakova SP. Alginate Lyases: Substrates, Structure, Properties, and Prospects of Application. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2018. [DOI: 10.1134/s1068162018040040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Mathieu S, Touvrey-Loiodice M, Poulet L, Drouillard S, Vincentelli R, Henrissat B, Skjåk-Bræk G, Helbert W. Ancient acquisition of "alginate utilization loci" by human gut microbiota. Sci Rep 2018; 8:8075. [PMID: 29795267 PMCID: PMC5966431 DOI: 10.1038/s41598-018-26104-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/04/2018] [Indexed: 01/29/2023] Open
Abstract
In bacteria from the phylum Bacteroidetes, the genes coding for enzymes involved in polysaccharide degradation are often colocalized and coregulated in so-called “polysaccharide utilization loci” (PULs). PULs dedicated to the degradation of marine polysaccharides (e.g. laminaran, ulvan, alginate and porphyran) have been characterized in marine bacteria. Interestingly, the gut microbiome of Japanese individuals acquired, by lateral transfer from marine bacteria, the genes involved in the breakdown of porphyran, the cell wall polysaccharide of the red seaweed used in maki. Sequence similarity analyses predict that the human gut microbiome also encodes enzymes for the degradation of alginate, the main cell wall polysaccharide of brown algae. We undertook the functional characterization of diverse polysaccharide lyases from family PL17, frequently found in marine bacteria as well as those of human gut bacteria. We demonstrate here that this family is polyspecific. Our phylogenetic analysis of family PL17 reveals that all alginate lyases, which have all the same specificity and mode of action, cluster together in a very distinct subfamily. The alginate lyases found in human gut bacteria group together in a single clade which is rooted deeply in the PL17 tree. These enzymes were found in PULs containing PL6 enzymes, which also clustered together in the phylogenetic tree of PL6. Together, biochemical and bioinformatics analyses suggest that acquisition of this system appears ancient and, because only traces of two successful transfers were detected upon inspection of PL6 and PL17 families, the pace of acquisition of marine polysaccharide degradation system is probably very slow.
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Affiliation(s)
- Sophie Mathieu
- CERMAV, CNRS and Grenoble Alpes Université, BP53, 38000, Grenoble Cedex 9, France
| | | | - Laurent Poulet
- CERMAV, CNRS and Grenoble Alpes Université, BP53, 38000, Grenoble Cedex 9, France
| | - Sophie Drouillard
- CERMAV, CNRS and Grenoble Alpes Université, BP53, 38000, Grenoble Cedex 9, France
| | - Renaud Vincentelli
- Centre National de la Recherche Scientifique (CNRS), UMR7257, Université Aix-Marseille, Marseille, 13288, France.,INRA, USC 1408 AFMB, 13288, Marseille, France
| | - Bernard Henrissat
- Centre National de la Recherche Scientifique (CNRS), UMR7257, Université Aix-Marseille, Marseille, 13288, France.,INRA, USC 1408 AFMB, 13288, Marseille, France.,Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Gudmund Skjåk-Bræk
- Department of Biotechnology, Norwegian University of Science and Technology, NTNU Sem Sælands vei 6-8, 7491, Trondheim, Norway
| | - William Helbert
- CERMAV, CNRS and Grenoble Alpes Université, BP53, 38000, Grenoble Cedex 9, France.
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Wendisch VF, Brito LF, Gil Lopez M, Hennig G, Pfeifenschneider J, Sgobba E, Veldmann KH. The flexible feedstock concept in Industrial Biotechnology: Metabolic engineering of Escherichia coli, Corynebacterium glutamicum, Pseudomonas, Bacillus and yeast strains for access to alternative carbon sources. J Biotechnol 2016; 234:139-157. [DOI: 10.1016/j.jbiotec.2016.07.022] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/25/2016] [Accepted: 07/28/2016] [Indexed: 11/28/2022]
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10
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Yang X, Li S, Wu Y, Yu W, Han F. Cloning and characterization of two thermo- and salt-tolerant oligoalginate lyases from marine bacterium Halomonas sp. FEMS Microbiol Lett 2016; 363:fnw079. [PMID: 27030725 DOI: 10.1093/femsle/fnw079] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2016] [Indexed: 11/13/2022] Open
Abstract
Two new alginate lyase genes, oalY1 and oalY2, have been cloned from the newly isolated marine bacterium Halomonas sp. QY114 and expressed in Escherichia coli The deduced alginate lyases, OalY1 and OalY2, belonged to polysaccharide lyase (PL) family 17 and showed less than 45% amino acid identity with all of the characterized oligoalginate lyases. OalY1 and OalY2 exhibited the highest activities at 45°C and 50°C, respectively. Both of them showed more than 50% of the highest activity at 60°C, and 20% at 80°C. In addition, they were salt-dependent and salt-tolerant since both of them showed the highest activity in the presence of 0.5 M NaCl and preserved 63% and 68% of activity in the presence of 3 M NaCl. Significantly, OalY1 and OalY2 could degrade both polyM and polyG blocks into alginate monosaccharides in an exo-lytic type, indicating that they are bifunctional alginate lyases. In conclusion, our study indicated that OalY1 and OalY2 are good candidates for alginate saccharification application, and the salt-tolerance may present an exciting new concept for biofuel production from native brown seaweeds.
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Affiliation(s)
- Xuemei Yang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China
| | - Shangyong Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China
| | - Ying Wu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China
| | - Wengong Yu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China
| | - Feng Han
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, PR China
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Kim HS, Chu YJ, Park CH, Lee EY, Kim HS. Site-Directed Mutagenesis-Based Functional Analysis and Characterization of Endolytic Lyase Activity of N- and C-Terminal Domains of a Novel Oligoalginate Lyase from Sphingomonas sp. MJ-3 Possessing Exolytic Lyase Activity in the Intact Enzyme. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2015; 17:782-792. [PMID: 26342491 DOI: 10.1007/s10126-015-9658-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 07/14/2015] [Indexed: 06/05/2023]
Abstract
A novel oligoalginate lyase from a marine bacterium, Sphingomonas sp. strain MJ-3, exhibited a unique alginate degradation activity that completely depolymerizes alginate to monomers through the formation of oligomers. In order to reveal the reason why MJ-3 oligoalginate can exhibit both endolytic and exolytic alginate lyase activities, ten mutants were developed and characterized on the basis of homology modeling. When the recombinant cell lysates containing the mutated proteins of MJ-3 oligoalginate lyase were allowed to react with alginate, the Asn177Ala, His178Ala, Tyr234Phe, His389Ala, and Tyr426Phe mutants showed reduced oligoalginate lyase activity, whereas the Arg236Ala mutant exhibited endolytic activity. Interestingly, the overexpressed Arg236Ala protein (79.6 kDa) was proteolytically cleaved into two fragments, i.e., the N-terminal 32.0-kDa and the C-terminal 47.6-kDa fragments. Both the purified N-terminal and C-terminal fragments showed endolytic lyase activity. They preferentially degraded a heteropolymeric (polyMG) block than poly-β-D-mannuronate (polyM) or poly-α-L-guluronate (polyG) blocks. These results suggest that the oligoalginate lyase activity of MJ-3 enzyme is derived from the cooperative interaction between the N- and C-terminal endolytic alginate lyase domains in the intact enzyme.
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Affiliation(s)
- Hae Sol Kim
- Department of Food Science and Biotechnology, Kyungsung University, Busan, 608-736, Republic of Korea
| | - Yu Jeong Chu
- Department of Food Science and Biotechnology, Kyungsung University, Busan, 608-736, Republic of Korea
| | - Chang-Ho Park
- Department of Chemical Engineering, Kyung Hee University, Gyeonggi-do, 446-701, Republic of Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering, Kyung Hee University, Gyeonggi-do, 446-701, Republic of Korea.
| | - Hee Sook Kim
- Department of Food Science and Biotechnology, Kyungsung University, Busan, 608-736, Republic of Korea.
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