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Tamburino R, Marcolongo L, Sannino L, Ionata E, Scotti N. Plastid Transformation: New Challenges in the Circular Economy Era. Int J Mol Sci 2022; 23:ijms232315254. [PMID: 36499577 PMCID: PMC9736159 DOI: 10.3390/ijms232315254] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
In a circular economy era the transition towards renewable and sustainable materials is very urgent. The development of bio-based solutions, that can ensure technological circularity in many priority areas (e.g., agriculture, biotechnology, ecology, green industry, etc.), is very strategic. The agricultural and fishing industry wastes represent important feedstocks that require the development of sustainable and environmentally-friendly industrial processes to produce and recover biofuels, chemicals and bioactive molecules. In this context, the replacement, in industrial processes, of chemicals with enzyme-based catalysts assures great benefits to humans and the environment. In this review, we describe the potentiality of the plastid transformation technology as a sustainable and cheap platform for the production of recombinant industrial enzymes, summarize the current knowledge on the technology, and display examples of cellulolytic enzymes already produced. Further, we illustrate several types of bacterial auxiliary and chitinases/chitin deacetylases enzymes with high biotechnological value that could be manufactured by plastid transformation.
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Affiliation(s)
- Rachele Tamburino
- CNR-IBBR, Institute of Biosciences and BioResources, 80055 Naples, Italy
| | | | - Lorenza Sannino
- CNR-IBBR, Institute of Biosciences and BioResources, 80055 Naples, Italy
| | - Elena Ionata
- CNR-IRET, Research Institute on Terrestrial Ecosystems, 80131 Naples, Italy
| | - Nunzia Scotti
- CNR-IBBR, Institute of Biosciences and BioResources, 80055 Naples, Italy
- Correspondence:
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2
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Bacterial chitinases: genetics, engineering and applications. World J Microbiol Biotechnol 2022; 38:252. [DOI: 10.1007/s11274-022-03444-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/18/2022] [Indexed: 11/16/2022]
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3
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Liu J, Xu Q, Wu Y, Sun D, Zhu J, Liu C, Liu W. Carbohydrate-binding modules of ChiB and ChiC promote the chitinolytic system of Serratia marcescens BWL1001. Enzyme Microb Technol 2022; 162:110118. [DOI: 10.1016/j.enzmictec.2022.110118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 08/22/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022]
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4
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Hou J, Mao D, Zhang Y, Huang R, Li L, Wang X, Luo Y. Long-term spatiotemporal variation of antimicrobial resistance genes within the Serratia marcescens population and transmission of S. marcescens revealed by public whole-genome datasets. JOURNAL OF HAZARDOUS MATERIALS 2022; 423:127220. [PMID: 34844350 DOI: 10.1016/j.jhazmat.2021.127220] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 09/05/2021] [Accepted: 09/10/2021] [Indexed: 06/13/2023]
Abstract
The development of antimicrobial resistance (AMR) is accelerated by the selective pressure exerted by the widespread use of antimicrobial drugs, posing an increasing danger to public health. However, long-term spatiotemporal variation in AMR genes in microorganisms, particularly in bacterial pathogens in response to antibiotic consumption, is not fully understood. Here, we used the NCBI RefSeq database to collect 478 whole-genome sequences for Serratia marcescens ranging from 1961 up to 2019, to document global long-term AMR trends in S. marcescens populations. In total, 100 AMR gene subtypes (16 AMR gene types) were detected in the genomes of S. marcescens populations. We identified 3 core resistance genes in S. marcescens genomes, and a high diversity of AMR genes was observed in S. marcescens genomes after corresponding antibiotics were discovered and introduced into clinical practice, suggesting the adaptation of S. marcescens populations to challenges with therapeutic antibiotics. Our findings indicate spatiotemporal variation of AMR genes in S. marcescens populations in relation to antibiotic consumption and suggest the potential transmission of S. marcescens isolates harboring AMR genes among countries and between the environment and the clinic, representing a public health threat that necessitates international solidarity to overcome.
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Affiliation(s)
- Jie Hou
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China
| | - Daqing Mao
- School of Medicine, Nankai University, Tianjin 300071, China
| | - Yulin Zhang
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China
| | - Ruiyang Huang
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China
| | - Linyun Li
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China
| | - Xiaolong Wang
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China
| | - Yi Luo
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China.
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The fish pathogen Aliivibrio salmonicida LFI1238 can degrade and metabolize chitin despite major gene loss in the chitinolytic pathway. Appl Environ Microbiol 2021; 87:e0052921. [PMID: 34319813 DOI: 10.1128/aem.00529-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The fish pathogen Aliivibrio (Vibrio) salmonicida LFI1238 is thought to be incapable of utilizing chitin as a nutrient source since approximately half of the genes representing the chitinolytic pathway are disrupted by insertion sequences. In the present study, we combined a broad set of analytical methods to investigate this hypothesis. Cultivation studies revealed that Al. salmonicida grew efficiently on N-acetylglucosamine (GlcNAc) and chitobiose ((GlcNAc)2), the primary soluble products resulting from enzymatic chitin hydrolysis. The bacterium was also able to grow on chitin particles, albeit at a lower rate compared to the soluble substrates. The genome of the bacterium contains five disrupted chitinase genes (pseudogenes) and three intact genes encoding a glycoside hydrolase family 18 (GH18) chitinase and two auxiliary activity family 10 (AA10) lytic polysaccharide monooxygenases (LPMOs). Biochemical characterization showed that the chitinase and LPMOs were able to depolymerize both α- and β-chitin to (GlcNAc)2 and oxidized chitooligosaccharides, respectively. Notably, the chitinase displayed up to 50-fold lower activity compared to other well-studied chitinases. Deletion of the genes encoding the intact chitinolytic enzymes showed that the chitinase was important for growth on β-chitin, whereas the LPMO gene-deletion variants only showed minor growth defects on this substrate. Finally, proteomic analysis of Al. salmonicida LFI1238 growth on β-chitin showed expression of all three chitinolytic enzymes, and intriguingly also three of the disrupted chitinases. In conclusion, our results show that Al. salmonicida LFI1238 can utilize chitin as a nutrient source and that the GH18 chitinase and the two LPMOs are needed for this ability. IMPORTANCE The ability to utilize chitin as a source of nutrients is important for the survival and spread of marine microbial pathogens in the environment. One such pathogen is Aliivibrio (Vibrio) salmonicida, the causative agent of cold water vibriosis. Due to extensive gene decay, many key enzymes in the chitinolytic pathway have been disrupted, putatively rendering this bacterium incapable of chitin degradation and utilization. In the present study we demonstrate that Al. salmonicida can degrade and metabolize chitin, the most abundant biopolymer in the ocean. Our findings shed new light on the environmental adaption of this fish pathogen.
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Lorentzen SB, Arntzen MØ, Hahn T, Tuveng TR, Sørlie M, Zibek S, Vaaje-Kolstad G, Eijsink VGH. Genomic and Proteomic Study of Andreprevotia ripae Isolated from an Anthill Reveals an Extensive Repertoire of Chitinolytic Enzymes. J Proteome Res 2021; 20:4041-4052. [PMID: 34191517 PMCID: PMC8802321 DOI: 10.1021/acs.jproteome.1c00358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Chitin is an abundant natural polysaccharide
that is hard to degrade
because of its crystalline nature and because it is embedded in robust
co-polymeric materials containing other polysaccharides, proteins,
and minerals. Thus, it is of interest to study the enzymatic machineries
of specialized microbes found in chitin-rich environments. We describe
a genomic and proteomic analysis of Andreprevotia ripae, a chitinolytic Gram-negative bacterium isolated from an anthill.
The genome of A. ripae encodes four secreted
family GH19 chitinases of which two were detected and upregulated
during growth on chitin. In addition, the genome encodes as many as
25 secreted GH18 chitinases, of which 17 were detected and 12 were
upregulated during growth on chitin. Finally, the single lytic polysaccharide
monooxygenase (LPMO) was strongly upregulated during growth on chitin.
Whereas 66% of the 29 secreted chitinases contained two carbohydrate-binding
modules (CBMs), this fraction was 93% (13 out of 14) for the upregulated
chitinases, suggesting an important role for these CBMs. Next to an
unprecedented multiplicity of upregulated chitinases, this study reveals
several chitin-induced proteins that contain chitin-binding CBMs but
lack a known catalytic function. These proteins are interesting targets
for discovery of enzymes used by nature to convert chitin-rich biomass.
The MS proteomic data have been deposited in the PRIDE database with
accession number PXD025087.
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Affiliation(s)
- Silje B Lorentzen
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
| | - Magnus Ø Arntzen
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
| | - Thomas Hahn
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Nobelstraße 12, 70569 Stuttgart, Germany
| | - Tina R Tuveng
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
| | - Susanne Zibek
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Nobelstraße 12, 70569 Stuttgart, Germany
| | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, NMBU - Norwegian University of Life Sciences, N-1433 Ås, Norway
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7
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Tully BG, Huntley JF. A Francisella tularensis Chitinase Contributes to Bacterial Persistence and Replication in Two Major U.S. Tick Vectors. Pathogens 2020; 9:pathogens9121037. [PMID: 33321814 PMCID: PMC7764610 DOI: 10.3390/pathogens9121037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/02/2020] [Accepted: 12/08/2020] [Indexed: 02/07/2023] Open
Abstract
Nearly 100 years after the first report of tick-borne tularemia, questions remain about the tick vector(s) that pose the greatest risk for transmitting Francisella tularensis (Ft), the causative agent of tularemia. Additionally, few studies have identified genes/proteins required for Ft to infect, persist, and replicate in ticks. To answer questions about vector competence and Ft transmission by ticks, we infected Dermacentor variabilis (Dv),Amblyomma americanum (Aa), and Haemaphysalis longicornis (Hl; invasive species from Asia) ticks with Ft, finding that although Aa ticks initially become infected with 1 order of magnitude higher Ft, Ft replicated more robustly in Dv ticks, and did not persist in Hl ticks. In transmission studies, both Dv and Aa ticks efficiently transmitted Ft to naïve mice, causing disease in 57% and 46% of mice, respectively. Of four putative Ft chitinases, FTL1793 is the most conserved among Francisella sp. We generated a ΔFTL1793 mutant and found that ΔFTL1793 was deficient for infection, persistence, and replication in ticks. Recombinant FTL1793 exhibited chitinase activity in vitro, suggesting that FTL1793 may provide an alternative energy source for Ft in ticks. Taken together, Dv ticks appear to pose a greater risk for harboring and transmitting tularemia and FTL1793 plays a major role in promoting tick infections by Ft.
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8
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Glycoside hydrolase family 18 chitinases: The known and the unknown. Biotechnol Adv 2020; 43:107553. [DOI: 10.1016/j.biotechadv.2020.107553] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/09/2020] [Accepted: 04/20/2020] [Indexed: 12/13/2022]
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9
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Ali MH, Aljadaani S, Khan J, Sindi I, Aboras M, Aly MM. Isolation and Molecular Identification of Two Chitinase Producing Bacteria from Marine Shrimp Shell Wastes. Pak J Biol Sci 2020; 23:139-149. [PMID: 31944073 DOI: 10.3923/pjbs.2020.139.149] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND AND OBJECTIVE Chitinase enzymes have a various application in the field of environmental, biotechnology and medical aspects. This study aimed to the production of the chitinolytic enzymes from different species of bacteria. MATERIALS AND METHODS Bacterial isolation from different habitats was carried out on agar medium containing chitin as carbon and nitrogen sources. The obtained bacteria (20) were characterized and screened again in chitin broth medium. RESULTS Out of 20 bacterial isolate, 2 new isolates, belonged to Streptomyces laurentii SN5 and Cellulosimicrobium funkei SN20, were the most active in chitin degradation compared to the other isolates. They have been characterized for the first time for their chitinase activity. They were identified using 16S rRNA gene analysis and in the liquid medium, the 2 isolates have enzyme activities of 0.533 and 0.537 U mL-1, respectively. The maximum chitinase production was obtained when those bacterial strains were grown in Luria-Bertani (LB) broth amended with 1% colloidal chitin, for 1 day and at temperature of 30°C. The optimum pH value for chitinase production was pH 7 for both S. laurentii and C. funkei. The enzyme has been purified using Sephadex G-100 and DEAE-Cellulose chromatography column and found to have a similar molecular size of ~50 kDa. CONCLUSION Those two bacterial species could be used in chitinase production and in the environmental recycling of disposable chitin wastes such as chitin from shrimp shell waste.
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10
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Proteomic and metabolic characterization of membrane vesicles derived from Streptococcus mutans at different pH values. Appl Microbiol Biotechnol 2020; 104:9733-9748. [DOI: 10.1007/s00253-020-10563-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/12/2020] [Accepted: 03/20/2020] [Indexed: 12/14/2022]
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Barcelos MCS, Ramos CL, Kuddus M, Rodriguez-Couto S, Srivastava N, Ramteke PW, Mishra PK, Molina G. Enzymatic potential for the valorization of agro-industrial by-products. Biotechnol Lett 2020; 42:1799-1827. [DOI: 10.1007/s10529-020-02957-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 06/30/2020] [Indexed: 12/13/2022]
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12
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Mekasha S, Tuveng TR, Askarian F, Choudhary S, Schmidt-Dannert C, Niebisch A, Modregger J, Vaaje-Kolstad G, Eijsink VGH. A trimodular bacterial enzyme combining hydrolytic activity with oxidative glycosidic bond cleavage efficiently degrades chitin. J Biol Chem 2020; 295:9134-9146. [PMID: 32398257 PMCID: PMC7335802 DOI: 10.1074/jbc.ra120.013040] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/07/2020] [Indexed: 12/17/2022] Open
Abstract
Findings from recent studies have indicated that enzymes containing more than one catalytic domain may be particularly powerful in the degradation of recalcitrant polysaccharides such as chitin and cellulose. Some known multicatalytic enzymes contain several glycoside hydrolase domains and one or more carbohydrate-binding modules (CBMs). Here, using bioinformatics and biochemical analyses, we identified an enzyme, Jd1381 from the actinobacterium Jonesia denitrificans, that uniquely combines two different polysaccharide-degrading activities. We found that Jd1381 contains an N-terminal family AA10 lytic polysaccharide monooxygenase (LPMO), a family 5 chitin-binding domain (CBM5), and a family 18 chitinase (Chi18) domain. The full-length enzyme, which seems to be the only chitinase produced by J. denitrificans, degraded both α- and β-chitin. Both the chitinase and the LPMO activities of Jd1381 were similar to those of other individual chitinases and LPMOs, and the overall efficiency of chitin degradation by full-length Jd1381 depended on its chitinase and LPMO activities. Of note, the chitin-degrading activity of Jd1381 was comparable with or exceeded the activities of combinations of well-known chitinases and an LPMO from Serratia marcescens Importantly, comparison of the chitinolytic efficiency of Jd1381 with the efficiencies of combinations of truncated variants-JdLPMO10 and JdCBM5-Chi18 or JdLPMO10-CBM5 and JdChi18-indicated that optimal Jd1381 activity requires close spatial proximity of the LPMO10 and the Chi18 domains. The demonstration of intramolecular synergy between LPMOs and hydrolytic enzymes reported here opens new avenues toward the development of efficient catalysts for biomass conversion.
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Affiliation(s)
- Sophanit Mekasha
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Tina Rise Tuveng
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Fatemeh Askarian
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Swati Choudhary
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, St. Paul, Minnesota, USA
| | - Claudia Schmidt-Dannert
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, St. Paul, Minnesota, USA
| | | | | | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
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Gangadharappa BS, Rajashekarappa S, Sathe G. Proteomic profiling of Serratia marcescens by high-resolution mass spectrometry. ACTA ACUST UNITED AC 2020; 10:123-135. [PMID: 32363156 PMCID: PMC7186543 DOI: 10.34172/bi.2020.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 08/07/2019] [Accepted: 09/03/2019] [Indexed: 11/09/2022]
Abstract
Introduction: Serratia marcescens, an opportunistic human pathogen, is reported as an important cause of nosocomial infection and outbreaks. Although the genome of S. marcescens (ATCC 13880) was completely sequenced by 2014, there are no studies on the proteomic profile of the organism. The objective of the present study is to analyze the protein profile of S. marcescens (ATCC 13880) using a high resolution mass spectrometry (MS). Methods: Serratia marcescens ATCC 13880 strain was grown in Luria-Bertani broth and the protein extracted was subjected to trypsin digestion, followed by basic reverse phase liquid chromatography fractionation. The peptide fractions were then analysed using Orbitrap Fusion Mass Spectrometry and the raw MS data were processed in Proteome Discoverer software. Results: The proteomic analysis identified 15 009 unique peptides mapping to 2541 unique protein groups, which corresponds to approximately 54% of the computationally predicted protein-coding genes. Bioinformatic analysis of these identified proteins showed their involvement in biological processes such as cell wall organization, chaperone-mediated protein folding and ATP binding. Pathway analysis revealed that some of these proteins are associated with bacterial chemotaxis and beta-lactam resistance pathway. Conclusion: To the best of our knowledge, this is the first high-throughput proteomics study of S. marcescens (ATCC 13880). These novel observations provide a crucial baseline molecular profile of the S. marcescens proteome which will prove to be helpful for the future research in understanding the host-pathogen interactions during infection, elucidating the mechanism of multidrug resistance, and developing novel diagnostic markers or vaccine for the disease.
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Affiliation(s)
- Bhavya Somalapura Gangadharappa
- Department of Biotechnology, M.S. Ramaiah Institute of Technology, Bengaluru-560054, Karnataka, India.,Visvesvaraya Technological University, Belagavi-590018, Karnataka, India
| | | | - Gajanan Sathe
- Institute of Bioinformatics, International Technology Park, Bangalore-560066, Karnataka, India.,Center for Molecular Medicine, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore-560029, Karnataka, India
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14
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Sørlie M, Horn SJ, Vaaje-Kolstad G, Eijsink VG. Using chitosan to understand chitinases and the role of processivity in the degradation of recalcitrant polysaccharides. REACT FUNCT POLYM 2020. [DOI: 10.1016/j.reactfunctpolym.2020.104488] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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15
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Le B, Yang SH. Microbial chitinases: properties, current state and biotechnological applications. World J Microbiol Biotechnol 2019; 35:144. [PMID: 31493195 DOI: 10.1007/s11274-019-2721-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 08/29/2019] [Indexed: 02/07/2023]
Abstract
Chitinases are a group of hydrolytic enzymes that catalyze chitin, nd are synthesized by a wide variety of organisms. In nature, microbial chitinases are primarily responsible for chitin decomposition. Several chitinases have been reported and characterized, and they are garnering increasing attention for their uses in a wide range of applications. In the food industry, the direct fermentation of seafood, such as crab and shrimp shells, using chitinolytic microorganisms has contributed to increased nutritional benefits through the enhancement of chitin degradation into chitooligosaccharides. These compounds have been demonstrated to improve human health through their antitumor, antimicrobial, immunomodulatory, antioxidant, and anti-inflammatory properties. Moreover, chitinase and chitinous materials are used in the food industry for other purposes, such as the production of single-cell proteins, chitooligosaccharides, N-acetyl D-glucosamines, biocontrol, functional foods, and various medicines. The functional properties and hydrolyzed products of chitinase, however, depend upon its source and physicochemical characteristics. The present review strives to clarify these perspectives and critically discusses the advances and limitations of microbial chitinase in the further production of functional foods.
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Affiliation(s)
- Bao Le
- Department of Biotechnology, Chonnam National University, Yeosu, Chonnam, 59626, Republic of Korea
| | - Seung Hwan Yang
- Department of Biotechnology, Chonnam National University, Yeosu, Chonnam, 59626, Republic of Korea.
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16
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Kimura M, Umeyama T, Wakita S, Okawa K, Sakaguchi M, Matoska V, Bauer PO, Oyama F. Direct comparison of chitinolytic properties and determination of combinatory effects of mouse chitotriosidase and acidic mammalian chitinase. Int J Biol Macromol 2019; 134:882-890. [DOI: 10.1016/j.ijbiomac.2019.05.097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/06/2019] [Accepted: 05/16/2019] [Indexed: 01/31/2023]
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17
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Sun X, Li Y, Tian Z, Qian Y, Zhang H, Wang L. A novel thermostable chitinolytic machinery of Streptomyces sp. F-3 consisting of chitinases with different action modes. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:136. [PMID: 31171937 PMCID: PMC6545677 DOI: 10.1186/s13068-019-1472-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 05/20/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND The biodegradation of chitin is an important part of the carbon and nitrogen cycles in nature. Speeding up the biotransformation of chitin substrates can not only reduce pollution, but also produce high value-added products. However, this process is strictly regulated by the catalytic efficiency of the chitinolytic machinery. Therefore, it is necessary to study the mode of action and compound mechanisms of different chitin-degrading enzymes in depth to improve the catalytic efficiency of the chitinolytic machinery. RESULTS The thermophilic bacterium Streptomyces sp. F-3 showed comparatively high chitin degradation activities. To elucidate the mechanism underlying chitin hydrolysis, six chitin degradation-related enzymes were identified in the extracellular proteome of Streptomyces sp. F-3, including three chitinases (SsChi18A, SsChi18B, and SsChi18C) from the GH18 family, one GH19 chitinase (SsChi19A), one GH20 β-N-acetylhexosaminidase (SsGH20A), and one lytic polysaccharide monooxygenase (SsLPMO10A) from the AA10 family. All were upregulated by chitin. The heterologously expressed hydrolases could withstand temperatures up to 70 °C and were stable at pH values of 4 to 11. Biochemical analyses displayed that these chitin degradation-related enzymes had different functions and thus showed synergistic effects during chitin degradation. Furthermore, based on structural bioinformatics data, we speculated that the different action modes among the three GH18 chitinases may be caused by loop differences in their active site architectures. Among them, SsChi18A is probably processive and mainly acts on polysaccharides, while SsChi18B and SsChi18C are likely endo-non-processive and displayed higher activity on the degradation of chitin oligosaccharides. In addition, proteomic data and synergy experiments also indicated the importance of SsLPMO10A, which could promote the activities of the hydrolases and increase the monosaccharide content in the reaction system, respectively. CONCLUSIONS In this article, the chitinolytic machinery of a thermophilic Streptomyces species was studied to explore the structural basis for the synergistic actions of chitinases from different GH18 subfamilies. The elucidation of the degradation mechanisms of these thermophilic chitinases will lay a theoretical foundation for the efficient industrialized transformation of natural chitin.
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Affiliation(s)
- Xiaomeng Sun
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Yingjie Li
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Zhennan Tian
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Yuanchao Qian
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Huaiqiang Zhang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Jimo Binhai Road, Qingdao, 266237 Shandong People’s Republic of China
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18
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Yan Q, Robert S, Brooks JP, Fong SS. Metabolic characterization of the chitinolytic bacterium Serratia marcescens using a genome-scale metabolic model. BMC Bioinformatics 2019; 20:227. [PMID: 31060515 PMCID: PMC6501404 DOI: 10.1186/s12859-019-2826-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 04/17/2019] [Indexed: 12/31/2022] Open
Abstract
Background Serratia marcescens is a chitinolytic bacterium that can potentially be used for consolidated bioprocessing to convert chitin to value-added chemicals. Currently, S. marcescens is poorly characterized and studies on intracellular metabolic and regulatory mechanisms would expedite development of bioprocessing applications. Results In this study, our goal was to characterize the metabolic profile of S. marcescens to provide insight for metabolic engineering applications and fundamental biological studies. Hereby, we constructed a constraint-based genome-scale metabolic model (iSR929) including 929 genes, 1185 reactions and 1164 metabolites based on genomic annotation of S. marcescens Db11. The model was tested by comparing model predictions with experimental data and analyzed to identify essential aspects of the metabolic network (e.g. 138 essential genes predicted). The model iSR929 was refined by integrating RNAseq data of S. marcescens growth on three different carbon sources (glucose, N-acetylglucosamine, and glycerol). Significant differences in TCA cycle utilization were found for growth on the different carbon substrates, For example, for growth on N-acetylglucosamine, S. marcescens exhibits high pentose phosphate pathway activity and nucleotide synthesis but low activity of the TCA cycle. Conclusions Our results show that S. marcescens model iSR929 can provide reasonable predictions and can be constrained to fit with experimental values. Thus, our model may be used to guide strain designs for metabolic engineering to produce chemicals such as 2,3-butanediol, N-acetylneuraminic acid, and n-butanol using S. marcescens. Electronic supplementary material The online version of this article (10.1186/s12859-019-2826-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Qiang Yan
- Department of Chemical and Life Science Engineering, School of Engineering, Virginia Commonwealth University, West Hall, Room 422, 601 West Main Street, P.O. Box 843028, Richmond, VA, 23284-3028, USA.
| | - Seth Robert
- Department of Chemical and Life Science Engineering, School of Engineering, Virginia Commonwealth University, West Hall, Room 422, 601 West Main Street, P.O. Box 843028, Richmond, VA, 23284-3028, USA
| | - J Paul Brooks
- Department of Statistical Sciences and Operations Research, Virginia Commonwealth University, P.O. Box 843083, Richmond, VA, 23284, USA.,Center for the study of Biological Complexity, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | - Stephen S Fong
- Department of Chemical and Life Science Engineering, School of Engineering, Virginia Commonwealth University, West Hall, Room 422, 601 West Main Street, P.O. Box 843028, Richmond, VA, 23284-3028, USA. .,Center for the study of Biological Complexity, Virginia Commonwealth University, Richmond, VA, 23284, USA.
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19
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Madhuprakash J, Dalhus B, Vaaje-Kolstad G, Sakuda S, Podile AR, Eijsink VGH, Sørlie M. Structural and Thermodynamic Signatures of Ligand Binding to the Enigmatic Chitinase D of Serratia proteamaculans. J Phys Chem B 2019; 123:2270-2279. [PMID: 30789732 DOI: 10.1021/acs.jpcb.8b11448] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Gram-negative bacteria Serratia marcescens and Serratia proteamaculans have efficient chitinolytic machineries that degrade chitin into N-acetylglucosamine (GlcNAc), which is used as a carbon and energy source. The enzymatic degradation of chitin in these bacteria occurs through the synergistic action of glycoside hydrolases (GHs) that have complementary activities; an endo-acting GH (ChiC) making random scissions on the polysaccharide chains and two exo-acting GHs mainly targeting single reducing (ChiA) and nonreducing (ChiB) chain ends. Both bacteria produce low amounts of a fourth GH18 (ChiD) with an unclear role in chitin degradation. Here, we have determined the thermodynamic signatures for binding of (GlcNAc)6 and the inhibitor allosamidin to SpChiD as well as the crystal structure of SpChiD in complex with allosamidin. The binding free energies for the two ligands are similar (Δ Gr° = -8.9 ± 0.1 and -8.4 ± 0.1 kcal/mol, respectively) with clear enthalpic penalties (Δ Hr° = 3.2 ± 0.1 and 1.8 ± 0.1 kcal/mol, respectively). Binding of (GlcNAc)6 is dominated by solvation entropy change (- TΔ Ssolv° = -17.4 ± 0.4 kcal/mol) and the conformational entropy change dominates for allosamidin binding (- TΔ Sconf° = -9.0 ± 0.2 kcal/mol). These signatures as well as the interactions with allosamidin are very similar to those of SmChiB suggesting that both enzymes are nonreducing end-specific.
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Affiliation(s)
- Jogi Madhuprakash
- Department of Chemistry, Biotechnology and Food Science , NMBU-Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway.,Department of Plant Sciences, School of Life Sciences , University of Hyderabad , Gachibowli, 500046 Hyderabad , India
| | - Bjørn Dalhus
- Department of Medical Biochemistry, Institute for Clinical Medicine , University of Oslo , P.O. Box 4950, Nydalen, N-0424 Oslo , Norway.,Department of Microbiology, Clinic for Laboratory Medicine , Oslo University Hospital, Rikshospitalet , P.O. Box 4950, Nydalen, N-0424 Oslo , Norway
| | - Gustav Vaaje-Kolstad
- Department of Chemistry, Biotechnology and Food Science , NMBU-Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
| | - Shohei Sakuda
- Department of Applied Biological Chemistry , University of Tokyo , Bunkyo-Ku, 113 Tokyo , Japan
| | - Appa Rao Podile
- Department of Plant Sciences, School of Life Sciences , University of Hyderabad , Gachibowli, 500046 Hyderabad , India
| | - Vincent G H Eijsink
- Department of Chemistry, Biotechnology and Food Science , NMBU-Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science , NMBU-Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
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20
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Tuveng TR, Eijsink VGH, Arntzen MØ. Proteomic Detection of Carbohydrate-Active Enzymes (CAZymes) in Microbial Secretomes. Methods Mol Biol 2019; 1871:159-177. [PMID: 30276740 DOI: 10.1007/978-1-4939-8814-3_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Secretomes from microorganisms growing on biomass contain carbohydrate-active enzymes (CAZymes) of potential biotechnological interest. By analyzing such secretomes, we may discover key enzymes involved in degradation processes and potentially infer the mode-of-action of biomass conversion. Some of these enzymes may have predicted functions in carbohydrate degradation, while others may not, while yet exhibiting a similar expression pattern; these latter enzymes constitute potential novel enzymes involved in the degradation process and provide a basis for further biochemical exploration. Hence, secretomes represent an important source for the study of both predicted and novel CAZymes. Here we describe a plate-based culturing technique that allows for collection of protein fractions that are highly enriched for secreted proteins, bound or unbound to the substrate, and which minimizes contamination by intracellular proteins trough unwanted cell lysis.
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Affiliation(s)
- Tina R Tuveng
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Magnus Ø Arntzen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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21
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Queiroz PS, Ruas FAD, Barboza NR, de Castro Borges W, Guerra-Sá R. Alterations in the proteomic composition of Serratia marcescens in response to manganese (II). BMC Biotechnol 2018; 18:83. [PMID: 30594179 PMCID: PMC6311052 DOI: 10.1186/s12896-018-0493-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 12/17/2018] [Indexed: 02/03/2023] Open
Abstract
Background Proteomics is an important tool for the investigation of dynamic physiological responses of microbes under heavy metal stress. To gain insight into how bacteria respond to manganese (II) and identify the proteins involved in Mn (II) oxidation, the shotgun proteomics approach was applied to a potential Mn (II)-oxidizing Serratia marcescens strain cultivated in the absence and presence of Mn (II). Results The LG1 strain, which grew equally well in the two conditions, was found to express a set of proteins related to cellular processes vital for survival, as well as proteins involved in adaptation and tolerance to Mn (II). The multicopper oxidase CueO was identified, indicating its probable participation in the Mn (II) bio-oxidation; however, its expression was not modulated by the presence of Mn (II). A set of proteins related to cell and metabolic processes vital to the cells were downregulated in the presence of Mn (II), while cell membrane-related proteins involved in the maintenance of cell integrity and survival under stress were upregulated under this condition. Conclusions These findings indicate that the LG1 strain may be applied successfully in the bioremediation of Mn (II), and the shotgun approach provides an efficient means for obtaining the total proteome of this species.
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Affiliation(s)
- Pollyana Santos Queiroz
- Laboratório de Bioquímica e Biologia Molecular, Departamento de Ciências Biológicas (DECBI) & Instituto de Ciências Exatas e Biológica (NUPEB), Campus Morro do Cruzeiro, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | - France Anne Dias Ruas
- Laboratório de Bioquímica e Biologia Molecular, Departamento de Ciências Biológicas (DECBI) & Instituto de Ciências Exatas e Biológica (NUPEB), Campus Morro do Cruzeiro, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | - Natália Rocha Barboza
- Laboratório de Bioquímica e Biologia Molecular, Departamento de Ciências Biológicas (DECBI) & Instituto de Ciências Exatas e Biológica (NUPEB), Campus Morro do Cruzeiro, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | - William de Castro Borges
- Laboratório de Enzimologia e Proteômica, Departamento de Ciências Biológicas (DECBI), Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil
| | - Renata Guerra-Sá
- Laboratório de Bioquímica e Biologia Molecular, Departamento de Ciências Biológicas (DECBI) & Instituto de Ciências Exatas e Biológica (NUPEB), Campus Morro do Cruzeiro, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
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22
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Madhuprakash J, Dalhus B, Rani TS, Podile AR, Eijsink VGH, Sørlie M. Key Residues Affecting Transglycosylation Activity in Family 18 Chitinases: Insights into Donor and Acceptor Subsites. Biochemistry 2018; 57:4325-4337. [DOI: 10.1021/acs.biochem.8b00381] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jogi Madhuprakash
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Bjørn Dalhus
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, P.O.
Box 4950, Nydalen, N-0424 Oslo, Norway
- Department of Microbiology, Clinic for Laboratory Medicine, Oslo University Hospital, Rikshospitalet, P.O. Box 4950, Nydalen, N-0424 Oslo, Norway
| | - T. Swaroopa Rani
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Appa Rao Podile
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India
| | - Vincent G. H. Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway
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23
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Microbial and viral chitinases: Attractive biopesticides for integrated pest management. Biotechnol Adv 2018; 36:818-838. [DOI: 10.1016/j.biotechadv.2018.01.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 12/28/2017] [Accepted: 01/02/2018] [Indexed: 02/01/2023]
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24
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Monge EC, Tuveng TR, Vaaje-Kolstad G, Eijsink VGH, Gardner JG. Systems analysis of the glycoside hydrolase family 18 enzymes from Cellvibrio japonicus characterizes essential chitin degradation functions. J Biol Chem 2018; 293:3849-3859. [PMID: 29367339 DOI: 10.1074/jbc.ra117.000849] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/10/2018] [Indexed: 01/01/2023] Open
Abstract
Understanding the strategies used by bacteria to degrade polysaccharides constitutes an invaluable tool for biotechnological applications. Bacteria are major mediators of polysaccharide degradation in nature; however, the complex mechanisms used to detect, degrade, and consume these substrates are not well-understood, especially for recalcitrant polysaccharides such as chitin. It has been previously shown that the model bacterial saprophyte Cellvibrio japonicus is able to catabolize chitin, but little is known about the enzymatic machinery underlying this capability. Previous analyses of the C. japonicus genome and proteome indicated the presence of four glycoside hydrolase family 18 (GH18) enzymes, and studies of the proteome indicated that all are involved in chitin utilization. Using a combination of in vitro and in vivo approaches, we have studied the roles of these four chitinases in chitin bioconversion. Genetic analyses showed that only the chi18D gene product is essential for the degradation of chitin substrates. Biochemical characterization of the four enzymes showed functional differences and synergistic effects during chitin degradation, indicating non-redundant roles in the cell. Transcriptomic studies revealed complex regulation of the chitin degradation machinery of C. japonicus and confirmed the importance of CjChi18D and CjLPMO10A, a previously characterized chitin-active enzyme. With this systems biology approach, we deciphered the physiological relevance of the glycoside hydrolase family 18 enzymes for chitin degradation in C. japonicus, and the combination of in vitro and in vivo approaches provided a comprehensive understanding of the initial stages of chitin degradation by this bacterium.
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Affiliation(s)
- Estela C Monge
- From the Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, Maryland 21250 and
| | - Tina R Tuveng
- the Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Ås, Norway
| | - Gustav Vaaje-Kolstad
- the Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Ås, Norway
| | - Vincent G H Eijsink
- the Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Ås, Norway
| | - Jeffrey G Gardner
- From the Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, Maryland 21250 and
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25
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Hamre AG, Frøberg EE, Eijsink VGH, Sørlie M. Thermodynamics of tunnel formation upon substrate binding in a processive glycoside hydrolase. Arch Biochem Biophys 2017; 620:35-42. [PMID: 28359644 DOI: 10.1016/j.abb.2017.03.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/20/2017] [Accepted: 03/23/2017] [Indexed: 11/18/2022]
Abstract
Glycoside hydrolases (GHs) catalyze the hydrolysis of glycosidic bonds and are key enzymes in carbohydrate metabolism. Efficient degradation of recalcitrant polysaccharides such as chitin and cellulose is accomplished due to synergistic enzyme cocktails consisting of accessory enzymes and mixtures of GHs with different modes of action and active site topologies. The substrate binding sites of chitinases and cellulases often have surface exposed aromatic amino acids and a tunnel or cleft topology. The active site of the exo-processive chitinase B (ChiB) from Serratia marcescens is partially closed, creating a tunnel-like catalytic cleft. To gain insight in the fundamental principles of substrate binding in this enzyme, we have studied the contribution of five key residues involved in substrate binding and tunnel formation to the thermodynamics of substrate binding. Mutation of Trp97, Phe190, Trp220 and Glu221, which are all part of the tunnel walls, resulted in significant less favorable conformational entropy change (ΔS°conf) upon binding (-TΔΔS°conf = ∼5 kcal/mol). This suggest that these residues are important for the structural rigidity and pre-shaping of the tunnel prior to binding. Mutation of Asp316, which, by forming a hydrogen bond to Trp97 is crucial in the active-site tunnel roof, resulted in a more favorable ΔS°conf relative to the wild type (-TΔΔS°conf = -2.2 kcal/mol). This shows that closing the tunnel-roof comes with an entropy cost, as previously suggested based on the crystal structures of GHs with tunnel topologies in complex with their substrates.
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Affiliation(s)
- Anne Grethe Hamre
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
| | - Emil Ebbestad Frøberg
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
| | - Vincent G H Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway.
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