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Ning L, Zhu B, Yao Z. Separation, purification and structural characterization of marine oligosaccharides: A comprehensive and systematic review of chromatographic methods. J Chromatogr A 2024; 1719:464755. [PMID: 38394786 DOI: 10.1016/j.chroma.2024.464755] [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: 10/26/2023] [Revised: 01/19/2024] [Accepted: 02/18/2024] [Indexed: 02/25/2024]
Abstract
Marine oligosaccharides have now been applied in a wide range of industry due to various kinds of physiological activities. However, the oligosaccharides with different polymeric degrees (Dps) differed in physiological activities and applicable fields. So it is promising and essential to separate, purify and structurally characterize these oligosaccharides for understanding their structure-function relationship. This review will summarize the lasted developments in the separation, purification and structural characterization of marine oligosaccharides, including the alginate oligosaccharides, carrageenan oligosaccharides, agar oligosaccharides, chitin oligosaccharides and chitosan oligosaccharides, emphasizing the successful examples of methods for separation and purification. Furthermore, an outlook for preparation of functional oligosaccharides in food biotechnology and agriculture fields is also included. This comprehensive review could definitely promote the utilization of marine functional polysaccharides for food and agriculture.
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Affiliation(s)
- Limin Ning
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China; School of Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, 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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2
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Ohnuma T, Tsujii J, Kataoka C, Yoshimoto T, Takeshita D, Lampela O, Juffer AH, Suginta W, Fukamizo T. Periplasmic chitooligosaccharide-binding protein requires a three-domain organization for substrate translocation. Sci Rep 2023; 13:20558. [PMID: 37996461 PMCID: PMC10667598 DOI: 10.1038/s41598-023-47253-y] [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: 07/04/2023] [Accepted: 11/10/2023] [Indexed: 11/25/2023] Open
Abstract
Periplasmic solute-binding proteins (SBPs) specific for chitooligosaccharides, (GlcNAc)n (n = 2, 3, 4, 5 and 6), are involved in the uptake of chitinous nutrients and the negative control of chitin signal transduction in Vibrios. Most translocation processes by SBPs across the inner membrane have been explained thus far by two-domain open/closed mechanism. Here we propose three-domain mechanism of the (GlcNAc)n translocation based on experiments using a recombinant VcCBP, SBP specific for (GlcNAc)n from Vibrio cholerae. X-ray crystal structures of unliganded or (GlcNAc)3-liganded VcCBP solved at 1.2-1.6 Å revealed three distinct domains, the Upper1, Upper2 and Lower domains for this protein. Molecular dynamics simulation indicated that the motions of the three domains are independent and that in the (GlcNAc)3-liganded state the Upper2/Lower interface fluctuated more intensively, compared to the Upper1/Lower interface. The Upper1/Lower interface bound two GlcNAc residues tightly, while the Upper2/Lower interface appeared to loosen and release the bound sugar molecule. The three-domain mechanism proposed here was fully supported by binding data obtained by thermal unfolding experiments and ITC, and may be applicable to other translocation systems involving SBPs belonging to the same cluster.
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Affiliation(s)
- Takayuki Ohnuma
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara, 631-8505, Japan.
- Agricultural Technology and Innovation Research Institute (ATIRI), Kindai University, 3327-204, Nakamachi, Nara, 631-8505, Japan.
| | - Jun Tsujii
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara, 631-8505, Japan
| | - Chikara Kataoka
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara, 631-8505, Japan
| | - Teruki Yoshimoto
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara, 631-8505, Japan
| | - Daijiro Takeshita
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba-Shi, Ibaraki, 305-8566, Japan
| | - Outi Lampela
- Biocenter Oulu, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
| | - André H Juffer
- Biocenter Oulu, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O.Box 5000, FI-90014, Oulu, Finland
| | - Wipa Suginta
- School of Biomolecular Science & Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley 555 Moo 1 Payupnai, Wangchan, Rayong, 21210, Thailand
| | - Tamo Fukamizo
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara, 631-8505, Japan.
- School of Biomolecular Science & Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley 555 Moo 1 Payupnai, Wangchan, Rayong, 21210, Thailand.
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3
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Jeong GJ, Khan F, Tabassum N, Kim YM. Chitinases as key virulence factors in microbial pathogens: Understanding their role and potential as therapeutic targets. Int J Biol Macromol 2023; 249:126021. [PMID: 37506799 DOI: 10.1016/j.ijbiomac.2023.126021] [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: 05/28/2023] [Revised: 07/20/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023]
Abstract
Chitinases are crucial for the survival of bacterial and fungal pathogens both during host infection and outside the host in the environment. Chitinases facilitate adhesion onto host cells, act as virulence factors during infection, and provide protection from the host immune system, making them crucial factors in the survival of microbial pathogens. Understanding the mechanisms behind chitinase action is beneficial to design novel therapeutics to control microbial infections. This review explores the role of chitinases in the pathogenesis of bacterial, fungal, and viral infections. The mechanisms underlying the action of chitinases of bacterial, fungal, and viral pathogens in host cells are thoroughly reviewed. The evolutionary relationships between chitinases of various bacterial, fungal, and viral pathogens are discussed to determine their involvement in processes, such as adhesion and host immune system modulation. Gaining a better understanding of the distribution and activity of chitinases in these microbial pathogens can help elucidate their role in the invasion and infection of host cells.
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Affiliation(s)
- Geum-Jae Jeong
- Department of Food Science and Technology, Pukyong National University, Busan 48513, Republic of Korea
| | - Fazlurrahman Khan
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea.
| | - Nazia Tabassum
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea
| | - Young-Mog Kim
- Department of Food Science and Technology, Pukyong National University, Busan 48513, Republic of Korea; Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea.
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4
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Sanram S, Aunkham A, Robinson R, Suginta W. Structural displacement model of chitooligosaccharide transport through chitoporin. J Biol Chem 2023; 299:105000. [PMID: 37394001 PMCID: PMC10406626 DOI: 10.1016/j.jbc.2023.105000] [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: 02/20/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/04/2023] Open
Abstract
VhChiP is a chitooligosaccharide-specific porin identified in the outer membrane of Vibrio campbellii type strain American Type Culture Collection BAA 1116. VhChiP contains three identical subunits, and in each subunit, the 19-amino acid N-terminal segment serves as a molecular plug (the "N-plug") that controls the closed/open dynamics of the neighboring pores. In this study, the crystal structures of VhChiP lacking the N-plug were determined in the absence and presence of chitohexaose. Binding studies of sugar-ligand interactions by single-channel recordings and isothermal microcalorimetry experiments suggested that the deletion of the N-plug peptide significantly weakened the sugar-binding affinity due to the loss of hydrogen bonds around the central affinity sites. Steered molecular dynamic simulations revealed that the movement of the sugar chain along the sugar passage triggered the ejection of the N-plug, while the H-bonds transiently formed between the reducing end GlcNAc units of the sugar chain with the N-plug peptide may help to facilitate sugar translocation. The findings enable us to propose the structural displacement model, which enables us to understand the molecular basis of chitooligosaccharide uptake by marine Vibrio bacteria.
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Affiliation(s)
- Surapoj Sanram
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Anuwat Aunkham
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Robert Robinson
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Wipa Suginta
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
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5
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Phengsakun G, Boonyarit B, Rungrotmongkol T, Suginta W. Structure-based virtual screening for potent inhibitors of GH-20 β-N-acetylglucosaminidase: classical and machine learning scoring functions, and molecular dynamics simulations. Comput Biol Chem 2023; 104:107856. [PMID: 37003097 DOI: 10.1016/j.compbiolchem.2023.107856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023]
Abstract
GH-20 β-N-acetylglucosaminidases (GlcNAcases) are promising targets in the development of antimicrobial agents against Vibrio infections in humans and aquatic animals. In this study, we set up structure-based virtual screening to identify potential GH-20 GlcNAcase inhibitors from the Reaxys commercial database, using VhGlcNAcase from V. campbellii type strain ATCC® BAA 1116 as the protein target and Redoxal as the reference ligand. Using ChemPLP and RF-Score-VS machine learning scoring functions, eight lead compounds were identified and further evaluated for protein interaction preference and pharmacological properties. Protein-ligand analysis demonstrated that all selected compounds interacted exclusively at subsite - 1 with five hydrophobic residues W487, W505, W546, W582 and V544 at site S1, and with two polar residues, D437 and E438, at site 3. For subsite + 1, the most common residues were R274 and E584 at site 2 and I397 and Q398 at site 4. Based on the data obtained from binding free energy changes (ΔG°binding), pharmacological property analysis and molecular dynamic simulations, two ChemPLP compounds, 338175 and 1146525, and one RF-Score-VS compound, 337447, were considered as the likely lead compounds. The most promising compound, 1146525, could serve as a scaffold for the future design of novel antimicrobial agents against Vibrio infections.
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Irshath AA, Rajan AP, Vimal S, Prabhakaran VS, Ganesan R. Bacterial Pathogenesis in Various Fish Diseases: Recent Advances and Specific Challenges in Vaccine Development. Vaccines (Basel) 2023; 11:vaccines11020470. [PMID: 36851346 PMCID: PMC9968037 DOI: 10.3390/vaccines11020470] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/08/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
Aquaculture is a fast-growing food sector but is plagued by a plethora of bacterial pathogens that infect fish. The rearing of fish at high population densities in aquaculture facilities makes them highly susceptible to disease outbreaks, which can cause significant economic loss. Thus, immunity development in fish through vaccination against various pathogens of economically important aquaculture species has been extensively studied and has been largely accepted as a reliable method for preventing infections. Vaccination studies in aquaculture systems are strategically associated with the economically and environmentally sustainable management of aquaculture production worldwide. Historically, most licensed fish vaccines have been developed as inactivated pathogens combined with adjuvants and provided via immersion or injection. In comparison, live vaccines can simulate a whole pathogenic illness and elicit a strong immune response, making them better suited for oral or immersion-based therapy methods to control diseases. Advanced approaches in vaccine development involve targeting specific pathogenic components, including the use of recombinant genes and proteins. Vaccines produced using these techniques, some of which are currently commercially available, appear to elicit and promote higher levels of immunity than conventional fish vaccines. These technological advancements are promising for developing sustainable production processes for commercially important aquatic species. In this review, we explore the multitude of studies on fish bacterial pathogens undertaken in the last decade as well as the recent advances in vaccine development for aquaculture.
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Affiliation(s)
- Aadil Ahmed Irshath
- Department of Biomedical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore 632 014, Tamil Nadu, India
| | - Anand Prem Rajan
- Department of Biomedical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore 632 014, Tamil Nadu, India
- Correspondence: (A.P.R.); (R.G.)
| | - Sugumar Vimal
- Department of Biochemistry, Saveetha Medical College & Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS), Thandalam, Chennai 600 077, Tamilnadu, India
| | - Vasantha-Srinivasan Prabhakaran
- Department of Bioinformatics, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai 600 077, Tamilnadu, India
| | - Raja Ganesan
- Institute for Liver and Digestive Diseases, College of Medicine, Hallym University, Chuncheon 24253, Republic of Korea
- Correspondence: (A.P.R.); (R.G.)
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Thakur D, Chauhan A, Jhilta P, Kaushal R, Dipta B. Microbial chitinases and their relevance in various industries. Folia Microbiol (Praha) 2023; 68:29-53. [PMID: 35972681 DOI: 10.1007/s12223-022-00999-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/31/2022] [Indexed: 01/09/2023]
Abstract
Chitin, the second most abundant biopolymer on earth after cellulose, is composed of β-1,4-N-acetylglucosamine (GlcNAc) units. It is widely distributed in nature, especially as a structural polysaccharide in the cell walls of fungi, the exoskeletons of crustaceans, insects, and nematodes. However, the principal commercial source of chitin is the shells of marine or freshwater invertebrates. Microbial chitinases are largely responsible for chitin breakdown in nature, and they play an important role in the ecosystem's carbon and nitrogen balance. Several microbial chitinases have been characterized and are gaining prominence for their applications in various sectors. The current review focuses on chitinases of microbial origin, their diversity, and their characteristics. The applications of chitinases in several industries such as agriculture, food, the environment, and pharmaceutical sectors are also highlighted.
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Affiliation(s)
- Deepali Thakur
- Dr Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan, 173230, Himachal Pradesh, India
| | - Anjali Chauhan
- Dr Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan, 173230, Himachal Pradesh, India
| | - Prakriti Jhilta
- Dr Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan, 173230, Himachal Pradesh, India
| | - Rajesh Kaushal
- Dr Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan, 173230, Himachal Pradesh, India
| | - Bhawna Dipta
- ICAR-Central Potato Research Institute, Shimla, 171001, Himachal Pradesh, India.
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8
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Thomas R, Fukamizo T, Suginta W. Bioeconomic production of high-quality chitobiose from chitin food wastes using an in-house chitinase from Vibrio campbellii. BIORESOUR BIOPROCESS 2022; 9:86. [PMID: 38647850 PMCID: PMC10991452 DOI: 10.1186/s40643-022-00574-8] [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: 05/24/2022] [Accepted: 08/05/2022] [Indexed: 11/10/2022] Open
Abstract
Marine Vibrio species are natural degraders of chitin and usually secrete high levels of chitinolytic enzymes to digest recalcitrant chitin to chitooligosaccharides. This study used an endochitinase (VhChiA) from Vibrio campbellii to produce high-quality chitobiose from crustacean chitins. The enzyme was shown to be fully active and stable over 24 h when BSA was used as an additive. When different chitin sources were tested, VhChiA preferentially digested shrimp and squid (α) chitins compared to crab (β) chitin and did not utilize non-chitin substrates. The overall yields of chitobiose obtained from small-scale production using a single-step reaction was 96% from shrimp, and 91% from squid pen and crab-shell chitins. Larger-scale production yielded 200 mg of chitobiose, with > 99% purity after a desalting and purification step using preparative HPLC. In conclusion, we report the employment of an in-house produced chitinase as an effective biocatalyst to rapidly convert chitin food wastes to chitobiose, in a quantity and quality suitable for use in research and commercial purposes. Chitobiose production by this economical and eco-friendly approach can be easily scaled up to obtain multi-gram quantities of chitobiose for chemo-enzymic synthesis of rare chitooligosaccharide derivatives and long chain chitooligosaccharides, as well as preparation of sugar-based functionalized nanomaterials.
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Affiliation(s)
- Reeba Thomas
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Payupnai, Wangchan District, Rayong, 21210, Thailand
| | - Tamo Fukamizo
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Payupnai, Wangchan District, Rayong, 21210, Thailand
| | - Wipa Suginta
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Payupnai, Wangchan District, Rayong, 21210, Thailand.
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Suginta W, Sanram S, Aunkham A, Winterhalter M, Schulte A. The C2 entity of chitosugars is crucial in molecular selectivity of the Vibrio campbellii chitoporin. J Biol Chem 2021; 297:101350. [PMID: 34715124 PMCID: PMC8608610 DOI: 10.1016/j.jbc.2021.101350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 10/21/2021] [Accepted: 10/22/2021] [Indexed: 12/14/2022] Open
Abstract
The marine bacterium Vibrio campbellii expresses a chitooligosaccharide-specific outer-membrane channel (chitoporin) for the efficient uptake of nutritional chitosugars that are externally produced through enzymic degradation of environmental host shell chitin. However, the principles behind the distinct substrate selectivity of chitoporins are unclear. Here, we employed black lipid membrane (BLM) electrophysiology, which handles the measurement of the flow of ionic current through porins in phospholipid bilayers for the assessment of porin conductivities, to investigate the pH dependency of chitosugar-chitoporin interactions for the bacterium's natural substrate chitohexaose and its deacetylated form, chitosan hexaose. We show that efficient passage of the N-acetylated chitohexaose through the chitoporin is facilitated by its strong affinity for the pore. In contrast, the deacetylated chitosan hexaose is impermeant; however, protonation of the C2 amino entities of chitosan hexaose allows it to be pulled through the channel in the presence of a transmembrane electric field. We concluded from this the crucial role of C2-substitution as the determining factor for chitoporin entry. A change from N-acetylamino- to amino-substitution effectively abolished the ability of approaching molecules to enter the chitoporin, with deacetylation leading to loss of the distinctive structural features of nanopore opening and pore access of chitosugars. These findings provide further understanding of the multistep pathway of chitin utilization by marine Vibrio bacteria and may guide the development of solid-state or genetically engineered biological nanopores for relevant technological applications.
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Affiliation(s)
- Wipa Suginta
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
| | - Surapoj Sanram
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Anuwat Aunkham
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Mathias Winterhalter
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Albert Schulte
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
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Fennell TG, Blackwell GA, Thomson NR, Dorman MJ. gbpA and chiA genes are not uniformly distributed amongst diverse Vibrio cholerae. Microb Genom 2021; 7:000594. [PMID: 34100695 PMCID: PMC8461464 DOI: 10.1099/mgen.0.000594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/26/2021] [Indexed: 11/18/2022] Open
Abstract
Members of the bacterial genus Vibrio utilize chitin both as a metabolic substrate and a signal to activate natural competence. Vibrio cholerae is a bacterial enteric pathogen, sub-lineages of which can cause pandemic cholera. However, the chitin metabolic pathway in V. cholerae has been dissected using only a limited number of laboratory strains of this species. Here, we survey the complement of key chitin metabolism genes amongst 195 diverse V. cholerae. We show that the gene encoding GbpA, known to be an important colonization and virulence factor in pandemic isolates, is not ubiquitous amongst V. cholerae. We also identify a putatively novel chitinase, and present experimental evidence in support of its functionality. Our data indicate that the chitin metabolic pathway within V. cholerae is more complex than previously thought, and emphasize the importance of considering genes and functions in the context of a species in its entirety, rather than simply relying on traditional reference strains.
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Affiliation(s)
- Thea G. Fennell
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK
- Churchill College, Storey’s Way, Cambridge, CB3 0DS, UK
- Present address: Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, UK
| | - Grace A. Blackwell
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK
- EMBL-EBI, Wellcome Genome Campus, Hinxton, CB10 1SD, UK
| | - Nicholas R. Thomson
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK
- London School of Hygiene and Tropical Medicine, Keppel St., Bloomsbury, London, WC1E 7HT, UK
| | - Matthew J. Dorman
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK
- Churchill College, Storey’s Way, Cambridge, CB3 0DS, UK
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11
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Aunkham A, Suginta W. Probing the physiological roles of the extracellular loops of chitoporin from Vibrio campbellii. Biophys J 2021; 120:2124-2137. [PMID: 33812846 PMCID: PMC8390830 DOI: 10.1016/j.bpj.2021.03.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 03/11/2021] [Accepted: 03/19/2021] [Indexed: 12/20/2022] Open
Abstract
VhChiP, a sugar-specific porin found on the outer membrane of Vibrio campbellii, is responsible for the transport of chitooligosaccharides, allowing the bacterium to thrive in aquatic environments using chitin as a nutrient. We previously showed that VhChiP is composed of three identical subunits, each containing a 16-stranded β-barrel connected by eight extracellular loops and eight short periplasmic turns. This study is focused on the specific roles of three prominent extracellular loops of VhChiP-L2, L3, and L8. The deletion of L2 completely disrupted the L2-L2 interactions, thus destabilizing the protein trimers as well as the integrity of the secondary structure. The deletion of L3 caused a drastic loss in the binding affinity for sugar substrates because of the absence of a cluster of key amino acid residues that form the affinity sites. The removal of L8 induced pronounced gating, which is highly responsive to elevated potentials. Our data provide further information on the important roles of the three prominent loops of VhChiP: loop L2 maintains the trimeric structure and the integrity of secondary structure, loop L3 controls the binding affinity for sugar substrates, and loop L8 retains the stably open state of the channel.
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Affiliation(s)
- Anuwat Aunkham
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Wipa Suginta
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
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12
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Meekrathok P, Bürger M, Porfetye AT, Kumsaoad S, Aunkham A, Vetter IR, Suginta W. Structural basis of chitin utilization by a GH20 β-N-acetylglucosaminidase from Vibrio campbellii strain ATCC BAA-1116. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2021; 77:674-689. [PMID: 33950022 PMCID: PMC8098473 DOI: 10.1107/s2059798321002771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 03/15/2021] [Indexed: 12/03/2022]
Abstract
Crystal structures of a GH20 β-N-acetylglucosaminidase from V. campbellii reveal substrate specificity in chitin utilization. Vibrio species play a crucial role in maintaining the carbon and nitrogen balance between the oceans and the land through their ability to employ chitin as a sole source of energy. This study describes the structural basis for the action of the GH20 β-N-acetylglucosaminidase (VhGlcNAcase) in chitin metabolism by Vibrio campbellii (formerly V. harveyi) strain ATCC BAA-1116. Crystal structures of wild-type VhGlcNAcase in the absence and presence of the sugar ligand, and of the unliganded D437A mutant, were determined. VhGlcNAcase contains three distinct domains: an N-terminal carbohydrate-binding domain linked to a small α+β domain and a C-terminal (β/α)8 catalytic domain. The active site of VhGlcNAcase has a narrow, shallow pocket that is suitable for accommodating a small chitooligosaccharide. VhGlcNAcase is a monomeric enzyme of 74 kDa, but its crystal structures show two molecules of enzyme per asymmetric unit, in which Gln16 at the dimeric interface of the first molecule partially blocks the entrance to the active site of the neighboring molecule. The GlcNAc unit observed in subsite −1 makes exclusive hydrogen bonds to the conserved residues Arg274, Tyr530, Asp532 and Glu584, while Trp487, Trp546, Trp582 and Trp505 form a hydrophobic wall around the −1 GlcNAc. The catalytic mutants D437A/N and E438A/Q exhibited a drastic loss of GlcNAcase activity, confirming the catalytic role of the acidic pair (Asp437–Glu438).
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Affiliation(s)
- Piyanat Meekrathok
- Biochemistry-Electrochemistry Research Unit, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Marco Bürger
- Max-Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Arthur T Porfetye
- Max-Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Sawitree Kumsaoad
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), 555 Payupnai, Wangchan, Rayong 21210, Thailand
| | - Anuwat Aunkham
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), 555 Payupnai, Wangchan, Rayong 21210, Thailand
| | - Ingrid R Vetter
- Max-Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Wipa Suginta
- Biochemistry-Electrochemistry Research Unit, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
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13
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Aunkham A, Schulte A, Sim WC, Chumjan W, Suginta W. Vibrio campbellii chitoporin: Thermostability study and implications for the development of therapeutic agents against Vibrio infections. Int J Biol Macromol 2020; 164:3508-3522. [PMID: 32858106 DOI: 10.1016/j.ijbiomac.2020.08.188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/22/2020] [Accepted: 08/23/2020] [Indexed: 02/02/2023]
Abstract
Vibrio campbellii (formerly Vibrio harveyi) is a bacterial pathogen that causes vibriosis, which devastates fisheries and aquaculture worldwide. V. campbellii expresses chitinolytic enzymes and chitin binding/transport proteins, which serve as excellent targets for antimicrobial agent development. We previously characterized VhChiP, a chitooligosaccharide-specific porin from the outer membrane of V. campbellii BAA-1116. This study employed far-UV circular dichroism and tryptophan fluorescence spectroscopy, together with single channel electrophysiology to demonstrate that the strong binding of chitoligosaccharides enhanced thermal stability of VhChiP. The alanine substitution of Trp136 at the center of the affinity sites caused a marked decrease in the binding affinity and decreased the thermal stability of VhChiP. Tryptophan fluorescence titrations over a range of temperatures showed greater free-energy changes on ligand binding (ΔG°binding) with increasing chain length of the chitooligosaccharides. Our findings suggest the possibility of designing stable channel-blockers, using sugar-based analogs that serve as antimicrobial agents, active against Vibrio infection.
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Affiliation(s)
- Anuwat Aunkham
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Payupnai, Wangchan, Rayong 21210, Thailand; School of Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Albert Schulte
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Payupnai, Wangchan, Rayong 21210, Thailand
| | - Wei Chung Sim
- School of Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Watcharin Chumjan
- School of Chemistry, Faculty of Engineering, Rajamangala University of Technology, Khon Kaen 40000, Thailand
| | - Wipa Suginta
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Payupnai, Wangchan, Rayong 21210, Thailand.
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14
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Meekrathok P, Stubbs KA, Aunkham A, Kaewmaneewat A, Kardkuntod A, Bulmer DM, Berg B, Suginta W. NAG‐thiazoline is a potent inhibitor of the
Vibrio campbellii
GH20 β‐
N
‐Acetylglucosaminidase. FEBS J 2020; 287:4982-4995. [DOI: 10.1111/febs.15283] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/15/2020] [Accepted: 03/04/2020] [Indexed: 12/17/2022]
Affiliation(s)
- Piyanat Meekrathok
- School of Chemistry Suranaree University of Technology Nakhon Ratchasima Thailand
| | - Keith A. Stubbs
- School of Molecular Sciences The University of Western Australia Crawley WA Australia
| | - Anuwat Aunkham
- School of Biomolecular Science and Engineering (BSE) Vidyasirimedhi Institute of Science and Technology (VISTEC) Rayong Thailand
| | - Anuphon Kaewmaneewat
- School of Biomolecular Science and Engineering (BSE) Vidyasirimedhi Institute of Science and Technology (VISTEC) Rayong Thailand
| | - Apinya Kardkuntod
- School of Biomolecular Science and Engineering (BSE) Vidyasirimedhi Institute of Science and Technology (VISTEC) Rayong Thailand
| | - David M. Bulmer
- Institute for Cell and Molecular Biosciences Newcastle University UK
| | - Bert Berg
- Institute for Cell and Molecular Biosciences Newcastle University UK
| | - Wipa Suginta
- School of Biomolecular Science and Engineering (BSE) Vidyasirimedhi Institute of Science and Technology (VISTEC) Rayong Thailand
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15
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He X, Yu M, Wu Y, Ran L, Liu W, Zhang XH. Two Highly Similar Chitinases from Marine Vibrio Species have Different Enzymatic Properties. Mar Drugs 2020; 18:E139. [PMID: 32120805 PMCID: PMC7143101 DOI: 10.3390/md18030139] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/21/2020] [Accepted: 02/25/2020] [Indexed: 12/16/2022] Open
Abstract
Chitinase, as one of the most important extracellular enzymes in the marine environment, has great ecological and applied values. In this study, two chitinases (Chi1557 and Chi4668) with 97.33% amino acid sequences identity were individually found in Vibrio rotiferianus and Vibrio harveyi. They both were encoding by 561 amino acids, but differed in 15 amino acids and showed different enzymatic properties. The optimal temperature and pH ranges were 45-50 °C and pH 5.0-7.0 for Chi1557, while ~50 °C and pH 3.0-6.0 for Chi4668. K+, Mg2+, and EDTA increased the enzymatic activity of Chi4668 significantly, yet these factors were inhibitory to Chi1557. Moreover, Chi1557 degraded colloidal chitin to produce (GlcNAc)2 and minor GlcNAc, whereas Chi4668 produce (GlcNAc)2 with minor (GlcNAc)3 and (GlcNAc)4. The Kcat/Km of Chi4668 was ~4.7 times higher than that of Chi1557, indicating that Chi4668 had stronger catalytic activity than Chi1557. Furthermore, site-directed mutagenesis was performed on Chi1557 focusing on seven conserved amino acid residues of family GH18 chitinases. Chi1557 was almost completely inactive after Glu154, Gln219, Tyr221, or Trp312 was individually mutated, retained ~50% activity after Tyr37 was mutated, and increased two times activity after Asp152 was mutated, indicating that these six amino acids were key sites for Chi1557.
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Affiliation(s)
- Xinxin He
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; (X.H.); (M.Y.); (Y.W.); (L.R.); (W.L.)
| | - Min Yu
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; (X.H.); (M.Y.); (Y.W.); (L.R.); (W.L.)
| | - Yanhong Wu
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; (X.H.); (M.Y.); (Y.W.); (L.R.); (W.L.)
| | - Lingman Ran
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; (X.H.); (M.Y.); (Y.W.); (L.R.); (W.L.)
| | - Weizhi Liu
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; (X.H.); (M.Y.); (Y.W.); (L.R.); (W.L.)
| | - Xiao-Hua Zhang
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; (X.H.); (M.Y.); (Y.W.); (L.R.); (W.L.)
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
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16
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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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17
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Meekrathok P, Stubbs KA, Suginta W. Potent inhibition of a GH20 exo-β-N-acetylglucosaminidase from marine Vibrio bacteria by reaction intermediate analogues. Int J Biol Macromol 2018; 115:1165-1173. [DOI: 10.1016/j.ijbiomac.2018.04.193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/14/2018] [Accepted: 04/30/2018] [Indexed: 02/04/2023]
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18
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Structural basis for chitin acquisition by marine Vibrio species. Nat Commun 2018; 9:220. [PMID: 29335469 PMCID: PMC5768706 DOI: 10.1038/s41467-017-02523-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 12/07/2017] [Indexed: 11/18/2022] Open
Abstract
Chitin, an insoluble polymer of N-acetylglucosamine, is one of the most abundant biopolymers on Earth. By degrading chitin, chitinolytic bacteria such as Vibrio harveyi are critical for chitin recycling and maintenance of carbon and nitrogen cycles in the world’s oceans. A decisive step in chitin degradation is the uptake of chito-oligosaccharides by an outer membrane protein channel named chitoporin (ChiP). Here, we report X-ray crystal structures of ChiP from V. harveyi in the presence and absence of chito-oligosaccharides. Structures without bound sugar reveal a trimeric assembly with an unprecedented closing of the transport pore by the N-terminus of a neighboring subunit. Substrate binding ejects the pore plug to open the transport channel. Together with molecular dynamics simulations, electrophysiology and in vitro transport assays our data provide an explanation for the exceptional affinity of ChiP for chito-oligosaccharides and point to an important role of the N-terminal gate in substrate transport. Chitin degrading bacteria are important for marine ecosystems. Here the authors structurally and functionally characterize the Vibrio harveyi outer membrane diffusion channel chitoporin and give mechanistic insights into chito-oligosaccharide uptake.
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19
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Cheba BA, Zaghloul TI, El-Mahdy AR, El-Massry MH. Effect of nitrogen sources and fermentation conditions on bacillus sp. R2 chitinase production. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.promfg.2018.03.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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20
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Suginta W, Sirimontree P, Sritho N, Ohnuma T, Fukamizo T. The chitin-binding domain of a GH-18 chitinase from Vibrio harveyi is crucial for chitin-chitinase interactions. Int J Biol Macromol 2016; 93:1111-1117. [DOI: 10.1016/j.ijbiomac.2016.09.066] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 09/06/2016] [Accepted: 09/18/2016] [Indexed: 11/26/2022]
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21
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Meekrathok P, Suginta W. Probing the Catalytic Mechanism of Vibrio harveyi GH20 β-N-Acetylglucosaminidase by Chemical Rescue. PLoS One 2016; 11:e0149228. [PMID: 26870945 PMCID: PMC4752478 DOI: 10.1371/journal.pone.0149228] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 01/28/2016] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Vibrio harveyi GH20 β-N-acetylglucosaminidase (VhGlcNAcase) is a chitinolytic enzyme responsible for the successive degradation of chitin fragments to GlcNAc monomers, activating the onset of the chitin catabolic cascade in marine Vibrios. METHODS Two invariant acidic pairs (Asp303-Asp304 and Asp437-Glu438) of VhGlcNAcase were mutated using a site-directed mutagenesis strategy. The effects of these mutations were examined and the catalytic roles of these active-site residues were elucidated using a chemical rescue approach. Enhancement of the enzymic activity of the VhGlcNAcase mutants was evaluated by a colorimetric assay using pNP-GlcNAc as substrate. RESULTS Substitution of Asp303, Asp304, Asp437 or Glu438 with Ala/Asn/Gln produced a dramatic loss of the GlcNAcase activity. However, the activity of the inactive D437A mutant was recovered in the presence of sodium formate. Our kinetic data suggest that formate ion plays a nucleophilic role by mimicking the β-COO-side chain of Asp437, thereby stabilizing the reaction intermediate during both the glycosylation and the deglycosylation steps. CONCLUSIONS Chemical rescue of the inactive D437A mutant of VhGlcNAcase by an added nucleophile helped to identify Asp437 as the catalytic nucleophile/base, and hence its acidic partner Glu438 as the catalytic proton donor/acceptor. GENERAL SIGNIFICANCE Identification of the catalytic nucleophile of VhGlcNAcases supports the proposal of a substrate-assisted mechanism of GH20 GlcNAcases, requiring the catalytic pair Asp437-Glu438 for catalysis. The results suggest the mechanistic basis of the participation of β-N-acetylglucosaminidase in the chitin catabolic pathway of marine Vibrios.
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Affiliation(s)
- Piyanat Meekrathok
- Biochemistry-Electrochemistry Research Unit and School of Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
| | - Wipa Suginta
- Biochemistry-Electrochemistry Research Unit and School of Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
- Center of Excellence in Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
- * E-mail:
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22
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Sirimontree P, Fukamizo T, Suginta W. Azide anions inhibit GH-18 endochitinase and GH-20 Exo β-N-acetylglucosaminidase from the marine bacterium Vibrio harveyi. J Biochem 2015; 159:191-200. [PMID: 26330565 DOI: 10.1093/jb/mvv087] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 08/02/2015] [Indexed: 11/14/2022] Open
Abstract
Vibrio harveyi is a bioluminescent marine bacterium that utilizes chitin as its sole source of energy. In the course of chitin degradation, the bacterium primarily secretes an endochitinase A (VhChiA) to hydrolyze chitin, generating chitooligosaccharide fragments that are readily transported into the cell and broken down to GlcNAc monomers by an exo β-N-acetylglucosaminidase (VhGlcNAcase). Here we report that sodium salts, especially sodium azide, inhibit two classes of these chitin-degrading enzymes (VhChiA and VhGlcNAcase) with distinct modes of action. Kinetic analysis of the enzymatic hydrolysis of pNP-glycoside substrates reveals that sodium azide inhibition of VhChiA has a mixed-type mode, but that it inhibits VhGlcNAcase competitively. We propose that azide anions inhibit chitinase activity by acting as strong nucleophiles that attack Cγ of the catalytic Glu or Cβ of the neighbouring Asp residues. Azide anions may bind not only to the catalytic centre, but also to the other subsites in the substrate-binding cleft of VhChiA. In contrast, azide anions may merely occupy the small-binding pocket of VhGlcNAcase, thereby blocking the accessibility of its active site by short-chain substrates.
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Affiliation(s)
- Paknisa Sirimontree
- Biochemistry-Electrochemistry Research Unit, School of Biochemistry, Suranaree University of Technology, Nakhon Ratchasima, Thailand and
| | - Tamo Fukamizo
- Department of Advanced Biosciences, Kinki University, Nara, Japan
| | - Wipa Suginta
- Biochemistry-Electrochemistry Research Unit, School of Biochemistry, Suranaree University of Technology, Nakhon Ratchasima, Thailand and
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Diversity of Vibrio spp in Karstic Coastal Marshes in the Yucatan Peninsula. PLoS One 2015; 10:e0134953. [PMID: 26252792 PMCID: PMC4529161 DOI: 10.1371/journal.pone.0134953] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 07/15/2015] [Indexed: 11/19/2022] Open
Abstract
Coastal bodies of water formed by the combination of seawater, underground rivers and rainwater comprise the systems with the greatest solar energy flow and biomass production on the planet. These characteristics make them reservoirs for a large number species, mainly microorganisms. Bacteria of the genus Vibrio are natural inhabitants of these environments and their presence is determined by variations in the nutrient, temperature and salinity cycles generated by the seasonal hydrologic behavior of these lagoon systems. This study determined the diversity of the genus Vibrio in 4 coastal bodies of water on the Yucatan Peninsula (Celestun Lagoon, Chelem Lagoon, Rosada Lagoon and Sabancuy Estuary). Using the molecular technique of 454 pyrosequencing, DNA extracted from water samples was analyzed and 32,807 reads were obtained belonging to over 20 culturable species of the genus Vibrio and related genera. OTU (operational taxonomic unit) richness and Chao2 and Shannon Weaver diversity indices were obtained with the database from this technique. Physicochemical and environmental parameters were determined and correlated with Vibrio diversity measured in OTUs.
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Sirimontree P, Suginta W, Sritho N, Kanda Y, Shinya S, Ohnuma T, Fukamizo T. Mutation strategies for obtaining chitooligosaccharides with longer chains by transglycosylation reaction of family GH18 chitinase. Biosci Biotechnol Biochem 2014; 78:2014-21. [DOI: 10.1080/09168451.2014.948373] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Abstract
Enhancing the transglycosylation (TG) activity of glycoside hydrolases does not always result in the production of oligosaccharides with longer chains, because the TG products are often decomposed into shorter oligosaccharides. Here, we investigated the mutation strategies for obtaining chitooligosaccharides with longer chains by means of TG reaction catalyzed by family GH18 chitinase A from Vibrio harveyi (VhChiA). HPLC analysis of the TG products from incubation of chitooligosaccharide substrates, GlcNAcn, with several mutant VhChiAs suggested that mutant W570G (mutation of Trp570 to Gly) and mutant D392N (mutation of Asp392 to Asn) significantly enhanced TG activity, but the TG products were immediately hydrolyzed into shorter GlcNAcn. On the other hand, the TG products obtained from mutants D313A and D313N (mutations of Asp313 to Ala and Asn, respectively) were not further hydrolyzed, leading to the accumulation of oligosaccharides with longer chains. The data obtained from the mutant VhChiAs suggested that mutations of Asp313, the middle aspartic acid residue of the DxDxE catalytic motif, to Ala and Asn are most effective for obtaining chitooligosaccharides with longer chains.
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Affiliation(s)
- Paknisa Sirimontree
- Biochemistry-Electrochemistry Research Unit, Schools of Chemistry and Biochemistry, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Wipa Suginta
- Biochemistry-Electrochemistry Research Unit, Schools of Chemistry and Biochemistry, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Natchanok Sritho
- Biochemistry-Electrochemistry Research Unit, Schools of Chemistry and Biochemistry, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Yuka Kanda
- Department of Advanced Biosciences, Kinki University, Nara, Japan
| | - Shoko Shinya
- Department of Advanced Biosciences, Kinki University, Nara, Japan
| | - Takayuki Ohnuma
- Department of Advanced Biosciences, Kinki University, Nara, Japan
| | - Tamo Fukamizo
- Department of Advanced Biosciences, Kinki University, Nara, Japan
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25
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Senol M, Nadaroglu H, Dikbas N, Kotan R. Purification of Chitinase enzymes from Bacillus subtilis bacteria TV-125, investigation of kinetic properties and antifungal activity against Fusarium culmorum. Ann Clin Microbiol Antimicrob 2014; 13:35. [PMID: 25112904 PMCID: PMC4236515 DOI: 10.1186/s12941-014-0035-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Accepted: 07/13/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chitin is the main structural component of cell walls of fungi, exoskeletons of insects and other arthropods and shells of crustaceans. Chitinase enzyme is capable of degrading chitin, and this enzyme can be used as a biological fungicide against phytopathogenic fungi, as well as an insecticide against insect pests. METHODS In this study, 158 isolates, which were derived from bacteria cultures isolated from leaves and root rhizospheres of certain plants in Turkey, were selected after confirming that they are not phytopathogenic based on the hypersensitivity test performed on tobacco; and antifungal activity test was performed against Fusarium culmorum, which is a pathogenic fungi that cause decomposition of roots of vegetables. Accordingly, chitinase enzyme activity assay was performed on 31 isolates that have an antifungal activity, and among them the isolate of Bacillus subtilis TV-125 was selected, which has demonstrated the highest activity. RESULTS Chitinase enzyme was purified by using ammonium sulphate and DEAE-sephadex ion exchange chromatography. Ammonium sulphate precipitation of chitinase enzyme from Bacillus subtilis TV-125 isolate was performed at maximum range of 0-20%, and 28.4-fold purification was obtained with a 13.4% of yield. Optimum activity of the purified enzyme was observed at pH 4.0 and at 50°C of temperature. In addition, it was identified that Bacillus subtilis TV-125A isolate retains 42% of its activity at 80°C temperature. CONCLUSION In the last phase of the study, chitinase enzyme purified from Bacillus subtilis TV-125A was tested on four fungal agents, although all the results were positive, it was particularly effective on F. culmorum according to the findings.
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26
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Production and Secretion of a RecombinantVibrio parahaemolyticusChitinase byEscherichia coliand Its Purification from the Culture Medium. Biosci Biotechnol Biochem 2014; 71:2848-51. [DOI: 10.1271/bbb.70389] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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27
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Yu P, Yan Y, Gu Q, Wang X. Codon optimisation improves the expression of Trichoderma viride sp. endochitinase in Pichia pastoris. Sci Rep 2013; 3:3043. [PMID: 24154717 PMCID: PMC3807108 DOI: 10.1038/srep03043] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 09/24/2013] [Indexed: 11/25/2022] Open
Abstract
The mature cDNA of endochitinase from Trichoderma viride sp. was optimised based on the codon bias of Pichia pastoris GS115 and synthesised by successive PCR; the sequence was then transformed into P. pastoris GS115 via electroporation. The transformant with the fastest growth rate on YPD plates containing 4 mg/mL G418 was screened and identified. This transformant produced 23.09 U/mL of the recombinant endochitinase, a 35% increase compared to the original strain bearing the wild-type endochitinase cDNA. The recombinant endochitinase was sequentially purified by ammonia sulphate precipitation, DE-52 anion-exchange chromatography and Sephadex G-100 size-exclusion chromatography. Thin-layer chromatography indicated that the purified endochitinase could hydrolyse chito-oligomers or colloidal chitin to generate diacetyl-chitobiose (GlcNAc)₂ as the main product. This study demonstrates (1) a means for high expression of Trichoderma viride sp. endochitinase in P. pastoris using codon optimisation and (2) the preparation of chito-oligomers using endochitinase.
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Affiliation(s)
- Ping Yu
- College of Food Science and Biotechnology, Zhejiang Gongshang University, 149 Jiaogong Road, Hangzhou 310035, Zhejiang Province, People's Republic of China
| | - Yuan Yan
- College of Food Science and Biotechnology, Zhejiang Gongshang University, 149 Jiaogong Road, Hangzhou 310035, Zhejiang Province, People's Republic of China
| | - Qing Gu
- College of Food Science and Biotechnology, Zhejiang Gongshang University, 149 Jiaogong Road, Hangzhou 310035, Zhejiang Province, People's Republic of China
| | - Xiangyang Wang
- College of Food Science and Biotechnology, Zhejiang Gongshang University, 149 Jiaogong Road, Hangzhou 310035, Zhejiang Province, People's Republic of China
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28
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Suginta W, Chumjan W, Mahendran KR, Janning P, Schulte A, Winterhalter M. Molecular uptake of chitooligosaccharides through chitoporin from the marine bacterium Vibrio harveyi. PLoS One 2013; 8:e55126. [PMID: 23383078 PMCID: PMC3558487 DOI: 10.1371/journal.pone.0055126] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 12/18/2012] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Chitin is the most abundant biopolymer in marine ecosystems. However, there is no accumulation of chitin in the ocean-floor sediments, since marine bacteria Vibrios are mainly responsible for a rapid turnover of chitin biomaterials. The catabolic pathway of chitin by Vibrios is a multi-step process that involves chitin attachment and degradation, followed by chitooligosaccharide uptake across the bacterial membranes, and catabolism of the transport products to fructose-6-phosphate, acetate and NH(3). PRINCIPAL FINDINGS This study reports the isolation of the gene corresponding to an outer membrane chitoporin from the genome of Vibrio harveyi. This porin, expressed in E. coli, (so called VhChiP) was found to be a SDS-resistant, heat-sensitive trimer. Immunoblotting using anti-ChiP polyclonal antibody confirmed the expression of the recombinant ChiP, as well as endogenous expression of the native protein in the V. harveyi cells. The specific function of VhChiP was investigated using planar lipid membrane reconstitution technique. VhChiP nicely inserted into artificial membranes and formed stable, trimeric channels with average single conductance of 1.8±0.13 nS. Single channel recordings at microsecond-time resolution resolved translocation of chitooligosaccharides, with the greatest rate being observed for chitohexaose. Liposome swelling assays showed no permeation of other oligosaccharides, including maltose, sucrose, maltopentaose, maltohexaose and raffinose, indicating that VhChiP is a highly-specific channel for chitooligosaccharides. CONCLUSION/SIGNIFICANCE We provide the first evidence that chitoporin from V. harveyi is a chitooligosaccharide specific channel. The results obtained from this study help to establish the fundamental role of VhChiP in the chitin catabolic cascade as the molecular gateway that Vibrios employ for chitooligosaccharide uptake for energy production.
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Affiliation(s)
- Wipa Suginta
- Biochemistry-Electrochemistry Research Unit, Schools of Chemistry and Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand.
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Multiple roles of Asp313 in the refined catalytic cycle of chitin degradation by Vibrio harveyi chitinase A. Biosci Biotechnol Biochem 2012; 76:2275-81. [PMID: 23221718 DOI: 10.1271/bbb.120559] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Three acidic residues in the DXDXE sequence motif are suggested to play a concerted role in the catalysis of Vibrio harveyi ChiA. An increase in the optimum pH of 0.8 units in mutant D313A/N indicates that Asp313 influences the pKa of the ionizing groups around the cleavage site. D313A showed greatly reduced kcat/Km and increased KD, suggesting that Asp313 participates in catalysis and ligand binding. Investigation of the enzyme-substrate interactions of V. harveyi ChiA and Serratia marcescens ChiB revealed two conformations of Asp313 and (-1)GlcNAc. The first conformation, likely to be the initial conformation, showed that the β-COOH of Asp313 only interacted with the -C=O of the N-acetyl group in the distorted sugar. The second conformation, formed from the first by concerted bond rotations, demonstrated hydrogen bonds between the Asp313 side chain and the -NH of the N-acetyl group and the γ-COOH of Glu315. Here we propose a further refinement of the catalytic cycle of chitin hydrolysis by family-18 chitinases that involves four steps: Step 1: Pre-priming. An acidic pair is formed between Asp311 and Asp313. Step 2: Substrate binding. The Asp313 side chain detaches from Asp311 and rotates to form a H-bond with the C=O of the 2-acetamido group of -1GlcNAc. Step 3: Bond cleavage. The side chain of Asp313 and the 2-acetamido group simultaneously rotate, permitting Asp313 to interact with the side chain of Glu315 and facilitating bond cleavage. Step 4: Formation of reaction intermediate. The transient (-1) C1-GlcNAc cation readily reacts with the 2-acetamido group, forming an oxazolinium ion intermediate. Further attack by a neighboring water results in retention of β-configuration of the degradation products.
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Itoi S, Kanomata Y, Uchida S, Kadokura K, Nishio T, Oku T, Sugita H. Effect of the C-terminal domain of Vibrio proteolyticus chitinase A on the chitinolytic activity in association with pH changes. Lett Appl Microbiol 2012; 54:441-6. [PMID: 22372468 DOI: 10.1111/j.1472-765x.2012.03228.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To reveal the cause of the difference in activity of chitinase A from Vibrio proteolyticus and chitinase A from a strain of Vibrio carchariae (a junior synonym of Vibrio harveyi), we investigated the pH-dependent activity of full-length V. proteolyticus chitinase A and a truncated recombinant corresponding to the V. harveyi form of chitinase A. METHODS AND RESULTS After overexpression in Escherichia coli strain DH5α, the full-length and truncated recombinant chitinases were purified by ammonium sulphate precipitation and anion exchange column chromatography. Chitinase activity was measured at various pH values using α-crystal and colloidal chitins as the substrate. The pH-dependent patterns of the relative specific activities for α-crystal chitin differed between the full-length and truncated recombinant chitinases, whereas those for colloidal chitin were similar to each other. CONCLUSION The difference in the activity of V. proteolyticus chitinase A and V. harveyi chitinase A might be partly due to a change in the pH dependence of the chitinase activities against α-crystal chitin, resulting from C-terminal processing. SIGNIFICANCE AND IMPACT OF STUDY The present results are important findings for not only ecological studies on the genus Vibrio in association with survival strategies, but also phylogenetic studies.
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Affiliation(s)
- S Itoi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, Japan.
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Sritho N, Suginta W. Role of Tyr-435 of Vibrio harveyi chitinase A in chitin utilization. Appl Biochem Biotechnol 2011; 166:1192-202. [PMID: 22194054 DOI: 10.1007/s12010-011-9504-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Accepted: 12/11/2011] [Indexed: 11/28/2022]
Abstract
Vibrio harveyi chitinase A or VhChiA (EC.3.2.1.14) is a member of GH-18 chitinases that catalyzes chitin degradation from marine biomaterials. Our earlier structural data of VhChiA suggested that Tyr-435 marks the ending of subsite +2 and may influence binding of the interacting substrate at the aglycone binding sites. This study reports the effects of Tyr-435 using site-directed mutagenesis technique. Mutation of Tyr-435 to Ala (mutant Y435A) enhanced both binding and catalytic efficiency of VhChiA, whereas substitution of Tyr-435 to Trp (mutant Y435W) lessened the ability of the enzyme to bind and hydrolyze chitin substrates. The increased activity of Y435A can be explained by partial removal of a steric clash around subsite (+2), thereby allowing a chitin chain to move beyond or to access the enzyme's active site from the aglycone side more straightforwardly.
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Affiliation(s)
- Natchanok Sritho
- Biochemistry-Electrochemistry Research Unit, Schools of Chemistry and Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
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Kudan S, Kuttiyawong K, Pichyangkura R. Carboxy-terminus truncations of Bacillus licheniformis SK-1 CHI72 with distinct substrate specificity. BMB Rep 2011; 44:375-80. [PMID: 21699749 DOI: 10.5483/bmbrep.2011.44.6.375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus licheniformis SK-1 naturally produces chitinase 72 (CHI72) with two truncation derivatives at the C-terminus, one with deletion of the chitin binding domain (ChBD), and the other with deletions of both fibronectin type III domain (FnIIID) and ChBD. We constructed deletions mutants of CHI72 with deletion of ChBD (CHI72ΔChBD) and deletions of both FnIIID and ChBD (CHI72ΔFnIIIDΔChBD), and studied their activity on soluble, amorphous and crystalline substrates. Interestingly, when equivalent amount of specific activity of each enzyme on soluble substrate was used, the product yield from CHI72- ΔChBD and CHI72ΔFnIIIDΔChBD on colloidal chitin was 2.5 and 1.6 fold higher than CHI72, respectively. In contrast, the product yield from CHI72ΔChBD and CHI72ΔFnIIID- ΔChBD on Β-chitin reduced to 0.7 and 0.5 fold of CHI72, respectively. These results suggest that CHI72 can modulate its substrate specificities through truncations of the functional domains at the C-terminus, producing a mixture of enzymes with elevated efficiency of hydrolysis.
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Affiliation(s)
- Sanya Kudan
- Biotechnology Program, Biochemistry Department, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.
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Suginta W, Chuenark D, Mizuhara M, Fukamizo T. Novel β-N-acetylglucosaminidases from Vibrio harveyi 650: cloning, expression, enzymatic properties, and subsite identification. BMC BIOCHEMISTRY 2010; 11:40. [PMID: 20920218 PMCID: PMC2955587 DOI: 10.1186/1471-2091-11-40] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 09/29/2010] [Indexed: 12/16/2022]
Abstract
Background Since chitin is a highly abundant natural biopolymer, many attempts have been made to convert this insoluble polysaccharide into commercially valuable products using chitinases and β-N-acetylglucosaminidases (GlcNAcases). We have previously reported the structure and function of chitinase A from Vibrio harveyi 650. This study t reports the identification of two GlcNAcases from the same organism and their detailed functional characterization. Results The genes encoding two new members of family-20 GlcNAcases were isolated from the genome of V. harveyi 650, cloned and expressed at a high level in E. coli. VhNag1 has a molecular mass of 89 kDa and an optimum pH of 7.5, whereas VhNag2 has a molecular mass of 73 kDa and an optimum pH of 7.0. The recombinant GlcNAcases were found to hydrolyze all the natural substrates, VhNag2 being ten-fold more active than VhNag1. Product analysis by TLC and quantitative HPLC suggested that VhNag2 degraded chitooligosaccharides in a sequential manner, its highest activity being with chitotetraose. Kinetic modeling of the enzymic reaction revealed that binding at subsites (-2) and (+4) had unfavorable (positive) binding free energy changes and that the binding pocket of VhNag2 contains four GlcNAc binding subsites, designated (-1),(+1),(+2), and (+3). Conclusions Two novel GlcNAcases were identified as exolytic enzymes that degraded chitin oligosaccharides, releasing GlcNAc as the end product. In living cells, these intracellular enzymes may work after endolytic chitinases to complete chitin degradation. The availability of the two GlcNAcases, together with the previously-reported chitinase A from the same organism, suggests that a systematic development of the chitin-degrading enzymes may provide a valuable tool in commercial chitin bioconversion.
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Affiliation(s)
- Wipa Suginta
- Biochemistry-Electrochemistry Research Unit, School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
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Lee SG, Koh HY, Han SJ, Park H, Na DC, Kim IC, Lee HK, Yim JH. Expression of recombinant endochitinase from the Antarctic bacterium, Sanguibacter antarcticus KOPRI 21702 in Pichia pastoris by codon optimization. Protein Expr Purif 2010; 71:108-14. [PMID: 20100576 DOI: 10.1016/j.pep.2010.01.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 12/23/2009] [Accepted: 01/19/2010] [Indexed: 11/28/2022]
Abstract
An endochitinase was previously purified and the gene was cloned from the psychrophilic Antarctic bacterium, Sanguibacter antarcticus (KCTC 13143). In the present study, recombinant endochitinase, rChi21702, was expressed using a yeast expression system (Pichia pastoris) and codon optimization. The expressed rChi21702 was purified by Phenyl-Sepharose column chromatography. Optimal expression yielded 1-mg purified enzyme from 1-L bioreactor culture. When p-NP-(GlcNAc)(2) was used as a substrate, the specific activity of the enzyme was determined to be 20U/mg. In vitro assays and thin-layer chromatography demonstrated that the recombinant enzyme has endochitinase activity that produces diacetyl-chitobiose as a dominant end product when chitooligomers, colloidal chitin, and the chromogenic p-NP-(GlcNAc)(2) are used as substrates. Optimal activity for rChi21702 was observed at 37 degrees C and a pH of 7.6. Interestingly, rChi21702 exhibited 63% of optimal activity at 10 degrees C and 44% activity at 0 degrees C. Taken together, the results indicate that rChi21702 has psychrotolerant endochitinase activity even after recombinant expression in yeast cells.
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Affiliation(s)
- Sung Gu Lee
- Polar BioCenter, Korea Polar Research Institute, Incheon 406-840, South Korea
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Li H, Greene LH. Sequence and structural analysis of the chitinase insertion domain reveals two conserved motifs involved in chitin-binding. PLoS One 2010; 5:e8654. [PMID: 20084296 PMCID: PMC2805709 DOI: 10.1371/journal.pone.0008654] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 12/05/2009] [Indexed: 01/01/2023] Open
Abstract
Background Chitinases are prevalent in life and are found in species including archaea, bacteria, fungi, plants, and animals. They break down chitin, which is the second most abundant carbohydrate in nature after cellulose. Hence, they are important for maintaining a balance between carbon and nitrogen trapped as insoluble chitin in biomass. Chitinases are classified into two families, 18 and 19 glycoside hydrolases. In addition to a catalytic domain, which is a triosephosphate isomerase barrel, many family 18 chitinases contain another module, i.e., chitinase insertion domain. While numerous studies focus on the biological role of the catalytic domain in chitinase activity, the function of the chitinase insertion domain is not completely understood. Bioinformatics offers an important avenue in which to facilitate understanding the role of residues within the chitinase insertion domain in chitinase function. Results Twenty-seven chitinase insertion domain sequences, which include four experimentally determined structures and span five kingdoms, were aligned and analyzed using a modified sequence entropy parameter. Thirty-two positions with conserved residues were identified. The role of these conserved residues was explored by conducting a structural analysis of a number of holo-enzymes. Hydrogen bonding and van der Waals calculations revealed a distinct subset of four conserved residues constituting two sequence motifs that interact with oligosaccharides. The other conserved residues may be key to the structure, folding, and stability of this domain. Conclusions Sequence and structural studies of the chitinase insertion domains conducted within the framework of evolution identified four conserved residues which clearly interact with the substrates. Furthermore, evolutionary studies propose a link between the appearance of the chitinase insertion domain and the function of family 18 chitinases in the subfamily A.
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Affiliation(s)
- Hai Li
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
| | - Lesley H. Greene
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
- * E-mail:
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Characteristics of cold-adaptive endochitinase from Antarctic bacterium Sanguibacter antarcticus KOPRI 21702. Enzyme Microb Technol 2009. [DOI: 10.1016/j.enzmictec.2009.07.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Suginta W, Pantoom S, Prinz H. Substrate binding modes and anomer selectivity of chitinase A from Vibrio harveyi. J Chem Biol 2009; 2:191-202. [PMID: 19568782 PMCID: PMC2763143 DOI: 10.1007/s12154-009-0021-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Accepted: 05/07/2009] [Indexed: 11/30/2022] Open
Abstract
High-performance liquid chromatography mass spectrometry (HPLC MS) was employed to assess the binding behaviors of various substrates to Vibrio harveyi chitinase A. Quantitative analysis revealed that hexaNAG preferred subsites −2 to +2 over subsites −3 to +2 and pentaNAG only required subsites −2 to +2, while subsites −4 to +2 were not used at all by both substrates. The results suggested that binding of the chitooligosaccharides to the enzyme essentially occurred in compulsory fashion. The symmetrical binding mode (−2 to +2) was favored presumably to allow the natural form of sugars to be utilized effectively. Crystalline α chitin was initially hydrolyzed into a diverse ensemble of chitin oligomers, providing a clear sign of random attacks that took place within chitin chains. However, the progressive degradation was shown to occur in greater extent at later time to complete hydrolysis. The effect of the reducing-end residues were also investigated by means of HPLC MS. Substitutions of Trp275 to Gly and Trp397 to Phe significantly shifted the anomer selectivity of the enzyme toward β substrates. The Trp275 mutation modulated the kinetic property of the enzyme by decreasing the catalytic constant (kcat) and the substrate specificity (kcat/Km) toward all substrates by five- to tenfold. In contrast, the Trp397 mutation weakened the binding strength at subsite (+2), thereby speeding up the rate of the enzymatic cleavage toward soluble substrates but slowing down the rate of the progressive degradation toward insoluble chitin.
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Affiliation(s)
- Wipa Suginta
- Biochemistry-Electrochemistry Research Unit, School of Chemistry and Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon, Ratchasima, 30000, Thailand,
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Chuang HH, Lin HY, Lin FP. Biochemical characteristics of C-terminal region of recombinant chitinase from Bacillus licheniformis: implication of necessity for enzyme properties. FEBS J 2008; 275:2240-54. [PMID: 18397326 DOI: 10.1111/j.1742-4658.2008.06376.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The functional and structural significance of the C-terminal region of Bacillus licheniformis chitinase was explored using C-terminal truncation mutagenesis. Comparative studies between full-length and truncated mutant molecules included initial rate kinetics, fluorescence and CD spectrometric properties, substrate binding and hydrolysis abilities, thermostability, and thermodenaturation kinetics. Kinetic analyses revealed that the overall catalytic efficiency, k(cat)/K(m), was slightly increased for the truncated enzymes toward the soluble 4-methylumbelliferyl-N-N'-diacetyl chitobiose or 4-methylumbelliferyl-N-N''-N'''-triacetyl chitotriose or insoluble alpha-chitin substrate. By contrast, changes to substrate affinity, K(m), and turnover rate, k(cat), varied considerably for both types of chitin substrates between the full-length and truncated enzymes. Both truncated enzymes exhibited significantly higher thermostabilities than the full-length enzyme. The truncated mutants retained similar substrate-binding specificities and abilities against the insoluble substrate but only had approximately 75% of the hydrolyzing efficiency of the full-length chitinase molecule. Fluorescence spectroscopy indicated that both C-terminal deletion mutants retained an active folding conformation similar to the full-length enzyme. However, a CD melting unfolding study was able to distinguish between the full-length and truncated mutant molecules by the two phases of apparent transition temperatures in the mutants. These results indicate that up to 145 amino acid residues, including the putative C-terminal chitin-binding region and the fibronectin (III) motif of B. licheniformis chitinase, could be removed without causing a seriously aberrant change in structure and a dramatic decrease in insoluble chitin hydrolysis. The results of the present study provide evidence demonstrating that the binding and hydrolyzing of insoluble chitin substrate for B. licheniformis chitinase was not dependent solely on the putative C-terminal chitin-binding region and the fibronectin (III) motif.
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Affiliation(s)
- Hsu-Han Chuang
- Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan
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A reducing-end-acting chitinase from Vibrio proteolyticus belonging to glycoside hydrolase family 19. Appl Microbiol Biotechnol 2008; 78:627-34. [DOI: 10.1007/s00253-008-1352-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 01/03/2008] [Accepted: 01/06/2008] [Indexed: 12/19/2022]
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Pantoom S, Songsiriritthigul C, Suginta W. The effects of the surface-exposed residues on the binding and hydrolytic activities of Vibrio carchariae chitinase A. BMC BIOCHEMISTRY 2008; 9:2. [PMID: 18205958 PMCID: PMC2265269 DOI: 10.1186/1471-2091-9-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Accepted: 01/21/2008] [Indexed: 11/10/2022]
Abstract
BACKGROUND Vibrio carchariae chitinase A (EC3.2.1.14) is a family-18 glycosyl hydrolase and comprises three distinct structural domains: i) the amino terminal chitin binding domain (ChBD); ii) the (alpha/beta)8 TIM barrel catalytic domain (CatD); and iii) the alpha + beta insertion domain. The predicted tertiary structure of V. carchariae chitinase A has located the residues Ser33 & Trp70 at the end of ChBD and Trp231 & Tyr245 at the exterior of the catalytic cleft. These residues are surface-exposed and presumably play an important role in chitin hydrolysis. RESULTS Point mutations of the target residues of V. carchariae chitinase A were generated by site-directed mutagenesis. With respect to their binding activity towards crystalline alpha-chitin and colloidal chitin, chitin binding assays demonstrated a considerable decrease for mutants W70A and Y245W, and a notable increase for S33W and W231A. When the specific hydrolyzing activity was determined, mutant W231A displayed reduced hydrolytic activity, whilst Y245W showed enhanced activity. This suggested that an alteration in the hydrolytic activity was not correlated with a change in the ability of the enzyme to bind to chitin polymer. A mutation of Trp70 to Ala caused the most severe loss in both the binding and hydrolytic activities, which suggested that it is essential for crystalline chitin binding and hydrolysis. Mutations varied neither the specific hydrolyzing activity against pNP-[GlcNAc]2, nor the catalytic efficiency against chitohexaose, implying that the mutated residues are not important in oligosaccharide hydrolysis. CONCLUSION Our data provide direct evidence that the binding as well as hydrolytic activities of V. carchariae chitinase A to insoluble chitin are greatly influenced by Trp70 and less influenced by Ser33. Though Trp231 and Tyr245 are involved in chitin hydrolysis, they do not play a major role in the binding process of crystalline chitin and the guidance of the chitin chain into the substrate binding cleft of the enzyme.
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Affiliation(s)
- Supansa Pantoom
- School of Biochemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
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Kadokura K, Sakamoto Y, Rokutani A, Ikegami T, Hirano T, Yamamoto M, Saito K, Hakamata W, Itoi S, Sugita H, Oku T, Nishio T. Purification, Characterization and Cloning of Vibrio parahaemolyticus Chitinolytic Enzymes and Application to Oligosaccharide Production. J Appl Glycosci (1999) 2008. [DOI: 10.5458/jag.55.157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Okay S, Tefon BE, Ozkan M, Ozcengiz G. Expression of chitinase A (chiA) gene from a local isolate of Serratia marcescens in Coleoptera-specific Bacillus thuringiensis. J Appl Microbiol 2007; 104:161-70. [PMID: 17927758 DOI: 10.1111/j.1365-2672.2007.03570.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS The present study focused on cloning and expression of chiA gene from a highly chitinolytic local isolate of Serratia marcescens in an anti-Coleopteran Bacillus thuringiensis and comparison of the characteristics of the native and recombinant ChiAs. METHODS AND RESULTS chiA gene from Ser. marcescens was cloned, sequenced and compared with the previously cloned chiA genes. chiA gene was PCR cloned and expressed in anti-Coleopteran B. thuringiensis strain 3023 as verified by Western blot analysis. Specific ChiA activity of the recombinant B. thuringiensis (strain 3023-SCHI) reached its highest level at 21st hour of growth (16.93 U mg(-1)), which was 5.2- and 1.3-fold higher than that of its parental strain and Ser. marcescens, respectively. Temperature and pH effects on native and recombinant ChiAs were next determined. The recombinant plasmid was quite stable over 240 generations. CONCLUSIONS Serratia marcescens ChiA was heterologously expressed in an anti-Coleopteran B. thuringiensis at levels even higher than that produced by the source organism. SIGNIFICANCE AND IMPACT OF THE STUDY Bacillus thuringiensis 3023-SCHI co-expressing anti-Coleopteran Cry3Aa protein and Ser. marcescens chitinase offers a viable alternative to the use of chitinolytic microbes/enzymes in combination with entamopathogenic bacteria for an increased potency because of synergistic interaction between them.
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Affiliation(s)
- S Okay
- Biological Sciences Department, Middle East Technical University, Ankara, Turkey
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Itoi S, Okamura T, Koyama Y, Sugita H. Chitinolytic bacteria in the intestinal tract of Japanese coastal fishes. Can J Microbiol 2007; 52:1158-63. [PMID: 17473885 DOI: 10.1139/w06-082] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intestinal bacteria from several coastal fish species were screened on 1/20 PYBG medium containing 0.2% colloidal chitin, and 361 bacteria capable of decomposing colloidal chitin were isolated. These isolates were subsequently screened on media containing either 0.5% alpha-chitin or 0.5% beta-chitin resulting in the identification of 31 alpha-chitinolytic and 275 beta-chitinolytic bacterial isolates. Partial 16S rRNA gene sequencing was carried out and homology searches of the resultant sequences against the DDBJ, EMBL, and GenBank databases revealed that the majority (99%) of the chitinolytic bacteria isolated belonged to the Vibrionaceae. Phylogenetic analysis using a Bayesian approach showed that the alpha-chitinolytic bacteria belonging to the Vibrionaceae formed a separate cluster from the non-alpha-chitinolytic bacteria in the Vibrionaceae.
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Affiliation(s)
- Shiro Itoi
- Department of Marine Science and Resources, Nihon University, Kanagawa, Japan
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Suginta W. Identification of chitin binding proteins and characterization of two chitinase isoforms from Vibrio alginolyticus 283. Enzyme Microb Technol 2007. [DOI: 10.1016/j.enzmictec.2007.01.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Itoi S, Kanomata Y, Koyama Y, Kadokura K, Uchida S, Nishio T, Oku T, Sugita H. Identification of a novel endochitinase from a marine bacterium Vibrio proteolyticus strain No. 442. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:1099-107. [PMID: 17690022 DOI: 10.1016/j.bbapap.2007.06.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 06/14/2007] [Accepted: 06/19/2007] [Indexed: 11/26/2022]
Abstract
Chitin binding proteins prepared from Vibrio proteolyticus were purified and the N-terminal amino-acid sequence of a protein from a 110-kDa band on SDS-PAGE was found to be 85-90% identical to the 22nd-41st residues of the N-termini of chitinase A precursor proteins from other vibrios. We cloned the corresponding gene, which encodes a putative protein of 850 amino acids containing a 26-residue signal sequence. The chitinase precursor from V. proteolyticus was 78-80% identical to those from Vibrio parahaemolyticus, Vibrio alginolyticus and Vibrio carchariae. However, the proteolytic cleavage site for C-terminal processing between R597 and K598 in the chitinase precursor of other vibrios was not observed in the amino acid sequence of V. proteolyticus, which instead had the sequence R600 and A601. Subsequently, full-length and truncated chitinases were generated in Escherichia coli. The specific activity of full-length chitinase expressed in E. coli was 17- and 20-folds higher for colloidal and alpha-chitins (insoluble substrate), respectively, than that of the C-terminal truncated enzyme. However, both recombinants showed similar hydrolysis patterns of hexa-N-acetyl-chitohexaose (soluble substrate), producing di-N-acetyl-chitobiose as major product on TLC analysis. We showed that the C-terminus of the V. proteolyticus chitinase A was important for expression of high specific activity against insoluble chitins.
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Affiliation(s)
- Shiro Itoi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-8510, Japan.
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Suginta W, Songsiriritthigul C, Kobdaj A, Opassiri R, Svasti J. Mutations of Trp275 and Trp397 altered the binding selectivity of Vibrio carchariae chitinase A. Biochim Biophys Acta Gen Subj 2007; 1770:1151-60. [PMID: 17490819 DOI: 10.1016/j.bbagen.2007.03.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Revised: 03/19/2007] [Accepted: 03/22/2007] [Indexed: 11/18/2022]
Abstract
Point mutations of the active-site residues Trp168, Tyr171, Trp275, Trp397, Trp570 and Asp392 were introduced to Vibrio carchariae chitinase A. The modeled 3D structure of the enzyme illustrated that these residues fully occupied the substrate binding cleft and it was found that their mutation greatly reduced the hydrolyzing activity against pNP-[GlcNAc](2) and colloidal chitin. Mutant W397F was the only exception, as it instead enhanced the hydrolysis of the pNP substrate to 142% and gave no activity loss towards colloidal chitin. The kinetic study with the pNP substrate demonstrated that the mutations caused impaired K(m) and k(cat) values of the enzyme. A chitin binding assay showed that mutations of the aromatic residues did not change the binding equilibrium. Product analysis by thin layer chromatography showed higher efficiency of W275G and W397F in G4-G6 hydrolysis over the wild type enzyme. Though the time course of colloidal chitin hydrolysis displayed no difference in the cleavage behavior of the chitinase variants, the time course of G6 hydrolysis exhibited distinct hydrolytic patterns between wild-type and mutants W275G and W397F. Wild type initially hydrolyzed G6 to G4 and G2, and finally G2 was formed as the major end product. W275G primarily created G2-G5 intermediates, and later G2 and G3 were formed as stable products. In contrast, W397F initially produced G1-G5, and then the high-M(r) intermediates (G3-G5) were broken down to G1 and G2 end products. This modification of the cleavage patterns of chitooligomers suggested that residues Trp275 and Trp397 are involved in defining the binding selectivity of the enzyme to soluble substrates.
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Affiliation(s)
- Wipa Suginta
- School of Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
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Giordano A, Andreotti G, Tramice A, Trincone A. Marine glycosyl hydrolases in the hydrolysis and synthesis of oligosaccharides. Biotechnol J 2006; 1:511-30. [PMID: 16892287 DOI: 10.1002/biot.200500036] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The marine ecosystem can be considered a rather unexplored source of biological material (e.g. natural substances with therapeutic activity) and can also be a surprising source of enzymes carrying new and interesting catalytic activities to be applied in biocatalysis. The use of glycosyl hydrolases from marine environments dates back to the end of the 1960s and was mainly focused on the development of sensitive and reliable hydrolytic methods for the analysis of sugar chains. As a result not all the benefits of a particular enzymatic activity have been investigated, especially regarding the transglycosylation potential of these enzymes for the synthesis of glycosidic bonds. In this review, the potential of marine sources will be demonstrated reporting on the few examples found in literature for the synthesis and hydrolysis of biologically relevant oligosaccharides catalyzed by glycosyl hydrolases of marine origin. Particular emphasis is given to the synthesis of glycosidic bonds, which is easy by the use of glycosyl hydrolases. Further aspects considered in this review are applications of these biocatalysts for vegetal waste treatment in recovering useful materials, for structural identification and for preparation of target materials from new purified polysaccharides, for the synthesis or modification of food-related compounds and for glycobiology related studies.
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Young VL, Simpson RM, Ward VK. Characterization of an exochitinase from Epiphyas postvittana nucleopolyhedrovirus (family Baculoviridae). J Gen Virol 2005; 86:3253-3261. [PMID: 16298970 DOI: 10.1099/vir.0.81262-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Baculovirus chitinases and other family 18 glycohydrolases have been shown to possess both exo- and endochitinase activities when assayed against fluorescent chito-oligosaccharides. Homology modelling of the chitinase ofEpiphyas postvittana nucleopolyhedrovirus(EppoNPV) againstSerratia marcescenschitinase A indicated that the enzyme possesses an N-terminal polycystic kidney 1 (PKD1) domain for chitin-substrate feeding and anα/βTIM barrel catalytic domain characteristic of a family 18 glycohydrolase. EppoNPV chitinase has many features in common with other baculovirus chitinases, including high amino acid identity, an N-terminal secretion signal and a functional C-terminal endoplasmic reticulum-retention sequence. EppoNPV chitinase displayed exo- and endochitinolytic activity against fluorescent chito-oligosaccharides, withKmvalues of 270±60 and 240±40 μM against 4MU-(GlcNAc)2and 20±6 and 14±7 μM against 4MU-(GlcNAc)3for native and recombinant versions of the enzyme, respectively. In contrast, digestion and thin-layer chromatography analysis of short-chain (GlcNAc)2–6chito-oligosaccharides without the fluorescent 4-methylumbelliferone (4MU) moiety produced predominantly (GlcNAc)2, indicating an exochitinase, although low-level endochitinase activity was detected. Digestion of long-chain colloidalβ-chitin and analysis by mass spectrometry identified a single 447 Da peak, representing a singly charged (GlcNAc)2complexed with a sodium adduct ion, confirming the enzyme as an exochitinase with no detectable endochitinolytic activity. Furthermore, (GlcNAc)3–6substrates, but not (GlcNAc)2, acted as inhibitors of EppoNPV chitinase. Short-chain substrates are unlikely to interact with the aromatic residues of the PKD1 substrate-feeding mechanism and hence may not accurately reflect the activity of these enzymes against native substrates. Based upon these results, the chitinase of the baculovirus EppoNPV is an exochitinase.
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Affiliation(s)
- Vivienne L Young
- Department of Microbiology and Immunology, School of Medical Sciences, University of Otago, PO Box 56, Dunedin, New Zealand
| | - Robert M Simpson
- Horticulture and Food Research Institute of New Zealand, Palmerston North, New Zealand
| | - Vernon K Ward
- Department of Microbiology and Immunology, School of Medical Sciences, University of Otago, PO Box 56, Dunedin, New Zealand
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Songsiriritthigul C, Yuvaniyama J, Robinson RC, Vongsuwan A, Prinz H, Suginta W. Expression, purification, crystallization and preliminary crystallographic analysis of chitinase A from Vibrio carchariae. Acta Crystallogr Sect F Struct Biol Cryst Commun 2005; 61:895-8. [PMID: 16511189 PMCID: PMC1991324 DOI: 10.1107/s1744309105027831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2005] [Accepted: 09/06/2005] [Indexed: 11/10/2022]
Abstract
Chitinase A of Vibrio carchariae was expressed in Escherichia coli M15 host cells as a 575-amino-acid fragment with full enzymatic activity using the pQE60 expression vector. The yield of the highly purified recombinant protein was approximately 70 mg per litre of bacterial culture. The molecular mass of the expressed protein was determined by HPLC/ESI-MS to be 63 770, including the hexahistidine tag. Crystals of recombinant chitinase A were grown to a suitable size for X-ray structure analysis in a precipitant containing 10%(v/v) PEG 400, 0.1 M sodium acetate pH 4.6 and 0.125 M CaCl2. The crystals belonged to the tetragonal space group P422, with two molecules per asymmetric unit and unit-cell parameters a = b = 127.64, c = 171.42 A. A complete diffraction data set was collected to 2.14 A resolution using a Rigaku/MSC R-AXIS IV++ detector system mounted on an RU-H3R rotating-anode X-ray generator.
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Affiliation(s)
- Chomphunuch Songsiriritthigul
- School of Biochemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
- National Synchrotron Research Center, Nakhon Ratchasima 30000, Thailand
| | - Jirundon Yuvaniyama
- Center for Excellence in Protein Structure and Function and Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Robert C. Robinson
- Institute of Molecular and Cell Biology, Proteos, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Archara Vongsuwan
- School of Biochemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Heino Prinz
- Max-Planck Institut für Molekulare Physiologie, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Wipa Suginta
- School of Biochemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
- Correspondence e-mail:
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Suginta W, Vongsuwan A, Songsiriritthigul C, Svasti J, Prinz H. Enzymatic properties of wild-type and active site mutants of chitinase A from Vibrio carchariae, as revealed by HPLC-MS. FEBS J 2005; 272:3376-86. [PMID: 15978043 DOI: 10.1111/j.1742-4658.2005.04753.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The enzymatic properties of chitinase A from Vibrio carchariae have been studied in detail by using combined HPLC and electrospray MS. This approach allowed the separation of alpha and beta anomers and the simultaneous monitoring of chitooligosaccharide products down to picomole levels. Chitinase A primarily generated beta-anomeric products, indicating that it catalyzed hydrolysis through a retaining mechanism. The enzyme exhibited endo characteristics, requiring a minimum of two glycosidic bonds for hydrolysis. The kinetics of hydrolysis revealed that chitinase A had greater affinity towards higher Mr chitooligomers, in the order of (GlcNAc)6 > (GlcNAc)4 > (GlcNAc)3, and showed no activity towards (GlcNAc)2 and pNP-GlcNAc. This suggested that the binding site of chitinase A was probably composed of an array of six binding subsites. Point mutations were introduced into two active site residues - Glu315 and Asp392 - by site-directed mutagenesis. The D392N mutant retained significant chitinase activity in the gel activity assay and showed approximately 20% residual activity towards chitooligosaccharides and colloidal chitin in HPLC-MS measurements. The complete loss of substrate utilization with the E315M and E315Q mutants suggested that Glu315 is an essential residue in enzyme catalysis. The recombinant wild-type enzyme acted on chitooligosaccharides, releasing higher quantities of small oligomers, while the D392N mutant favored the formation of transient intermediates. Under standard hydrolytic conditions, all chitinases also exhibited transglycosylation activity towards chitooligosaccharides and pNP-glycosides, yielding picomole quantities of synthesized chitooligomers. The D392N mutant displayed strikingly greater efficiency in oligosaccharide synthesis than the wild-type enzyme.
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Affiliation(s)
- Wipa Suginta
- School of Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
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