1
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Catechol modification of non-woven chitosan gauze for enhanced hemostatic efficacy. Carbohydr Polym 2022; 286:119319. [DOI: 10.1016/j.carbpol.2022.119319] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/15/2022] [Accepted: 03/02/2022] [Indexed: 01/06/2023]
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2
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Gong KQ, Frevert C, Manicone AM. Deletion of LysM in LysMCre Recombinase Homozygous Mice is Non-contributory in LPS-Induced Acute Lung Injury. Lung 2019; 197:819-823. [PMID: 31705272 DOI: 10.1007/s00408-019-00286-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 10/19/2019] [Indexed: 11/24/2022]
Abstract
Lysozyme is an important component of the innate immune system and has roles in peptidoglycan cleavage of gram-positive organisms. Myeloid cells highly express the isoform, lysozyme M, and its promoter has been used to direct Cre recombinase expression to target deletion of floxed genes in myeloid cells. However, generation of the LysMCre mouse effectively disrupts the LysM gene, and mice homozygous for the Cre allele lack the LysM gene product. To test the contribution of LysM in sterile acute lung injury, we generated LysMCre mice homozygous for the Cre allele (+/+) or wild-type allele (-/-). These mice were challenged with LPS delivered via oropharygneal aspiration. Mice were monitored and weighed daily, and BAL cell counts, differential, protein, and cytokine levels were assessed at days 2 and 4. LysMCre+/+ and LysMCre-/- had similar weight loss and recovery, and similar inflammatory responses to LPS at days 2 and 4. These findings indicate that loss of LysM and expression of Cre recombinase are non-contributory in sterile acute lung injury.
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Affiliation(s)
- Ke-Qin Gong
- Division of Pulmonary and Critical Care Medicine, Center for Lung Biology, University of Washington, Seattle, WA, USA
| | - Charles Frevert
- Department of Comparative Medicine, Center for Lung Biology, University of Washington, Seattle, WA, USA
| | - Anne M Manicone
- Division of Pulmonary and Critical Care Medicine, Center for Lung Biology, University of Washington, Seattle, WA, USA.
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3
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Influence of Preparation Methods of Chitooligosaccharides on Their Physicochemical Properties and Their Anti-Inflammatory Effects in Mice and in RAW264.7 Macrophages. Mar Drugs 2018; 16:md16110430. [PMID: 30400250 PMCID: PMC6265923 DOI: 10.3390/md16110430] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 10/19/2018] [Accepted: 10/24/2018] [Indexed: 11/17/2022] Open
Abstract
The methods to obtain chitooligosaccharides are tightly related to the physicochemical properties of the end products. Knowledge of these physicochemical characteristics is crucial to describing the biological functions of chitooligosaccharides. Chitooligosaccharides were prepared either in a single-step enzymatic hydrolysis using chitosanase, or in a two-step chemical-enzymatic hydrolysis. The hydrolyzed products obtained in the single-step preparation were composed mainly of 42% fully deacetylated oligomers plus 54% monoacetylated oligomers, and they attenuated the inflammation in lipopolysaccharide-induced mice and in RAW264.7 macrophages. However, chitooligosaccharides from the two-step preparation were composed of 50% fully deacetylated oligomers plus 27% monoacetylated oligomers and, conversely, they promoted the inflammatory response in both in vivo and in vitro models. Similar proportions of monoacetylated and deacetylated oligomers is necessary for the mixtures of chitooligosaccharides to achieve anti-inflammatory effects, and it directly depends on the preparation method to which chitosan was submitted.
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4
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Pechsrichuang P, Lorentzen SB, Aam BB, Tuveng TR, Hamre AG, Eijsink VGH, Yamabhai M. Bioconversion of chitosan into chito-oligosaccharides (CHOS) using family 46 chitosanase from Bacillus subtilis (BsCsn46A). Carbohydr Polym 2018; 186:420-428. [PMID: 29456005 DOI: 10.1016/j.carbpol.2018.01.059] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 01/13/2018] [Accepted: 01/17/2018] [Indexed: 01/08/2023]
Abstract
BsCsn46A, a GH family 46 chitosanase from Bacillus subtilis had been previously shown to have potential for bioconversion of chitosan to chito-oligosaccharides (CHOS). However, so far, in-depth analysis of both the mode of action of this enzyme and the composition of its products were lacking. In this study, we have employed size exclusion chromatography, 1H NMR, and mass spectrometry to reveal that BsCsn46A can rapidly cleave chitosans with a wide-variety of acetylation degrees, using a non-processive endo-mode of action. The composition of the product mixtures can be tailored by varying the degree of acetylation of the chitosan and the reaction time. Detailed analysis of product profiles revealed differences compared to other chitosanases. Importantly, BsCsn46A seems to be one of the fastest chitosanases described so far. The detailed analysis of preferred endo-binding modes using H218O showed that a hexameric substrate has three productive binding modes occurring with similar frequencies.
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Affiliation(s)
- Phornsiri Pechsrichuang
- Molecular Biotechnology Laboratory, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.
| | - Silje B Lorentzen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway.
| | - Berit B Aam
- BioCHOS AS, co/Incubator Ås, P.O. Box 19, 1431 Ås, Norway.
| | - Tina R Tuveng
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway.
| | - Anne G Hamre
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway.
| | - Vincent G H Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway.
| | - Montarop Yamabhai
- Molecular Biotechnology Laboratory, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.
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5
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Feng Y, Kitaoku Y, Tanaka J, Taira T, Ohnuma T, Aachmann FL, Fukamizo T. Mode of action and specificity of a chitinase from unicellular microalgae, Euglena gracilis. PLANT MOLECULAR BIOLOGY 2018; 97:553-564. [PMID: 30083952 DOI: 10.1007/s11103-018-0759-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/26/2018] [Indexed: 06/08/2023]
Abstract
Euglena gracilis is a unicellular microalga showing characteristics of both plants and animals, and extensively used as a model organism in the research works of biochemistry and molecular biology. Biotechnological applications of E. gracilis have been conducted for production of numerous important compounds. However, chitin-mediated defense system intensively studied in higher plants remains to be investigated in this microalga. Recently, Taira et al. (Biosci Biotechnol Biochem 82:1090-1100, 2018) isolated a unique chitinase gene, comprising two catalytic domains almost homologous to each other (Cat1 and Cat2) and two chitin-binding domains (CBD1 and CBD2), from E. gracilis. We herein examined the mode of action and the specificity of the recombinant Cat2 by size exclusion chromatography and NMR spectroscopy. Both Cat1 and Cat2 appeared to act toward chitin substrate with non-processive/endo-splitting mode, recognizing two contiguous N-acetylglucosamine units at subsites - 2 and - 1. This is the first report on a chitinase having two endo-splitting catalytic domains. A cooperative action of two different endo-splitting domains may be advantageous for defensive action of the E. gracilis chitinase. The unicellular alga, E. gracilis, produces a chitinase consisting of two GH18 catalytic domains (Cat1 and Cat2) and two CBM18 chitin-binding domains (CBD1 and CBD2). Here, we produced a recombinant protein of the Cat2 domain to examine its mode of action as well as specificity. Cat2 hydrolyzed N-acetylglucosamine (A) oligomers (An, n = 4, 5, and 6) and partially N-acetylated chitosans with a non-processive/endo-splitting mode of action. NMR analysis of the product mixture from the enzymatic digestion of chitosan revealed that the reducing ends were exclusively A-unit, and the nearest neighbors of the reducing ends were mostly A-unit but not exclusively. Both A-unit and D-unit were found at the non-reducing ends and the nearest neighbors. These results indicated strong and absolute specificities for subsites - 2 and - 1, respectively, and no preference for A-unit at subsites + 1 and + 2. The same results were obtained from sugar sequence analysis of the individual enzymatic products from the chitosans. The subsite specificities of Cat2 are similar to those of GH18 human chitotriosidase, but differ from those of plant GH18 chitinases. Since the structures of Cat1 and Cat2 resemble to each other (99% similarity in amino acid sequences), Cat1 may hydrolyze the substrate with the same mode of action. Thus, the E. gracilis chitinase appears to act toward chitin polysaccharide chain through a cooperative action of the two endo-splitting catalytic domains, recognizing two contiguous A-units at subsites - 2 and - 1.
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Affiliation(s)
- Yiming Feng
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Yoshihito Kitaoku
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara, 631-8505, Japan
| | - Jun Tanaka
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara, 631-8505, Japan
| | - Toki Taira
- Department of Bioscience and Biotechnology, University of the Ryukyus, Nishihara-cho, 903-0213, Japan
| | - Takayuki Ohnuma
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara, 631-8505, Japan
| | - Finn L Aachmann
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Tamo Fukamizo
- Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara, 631-8505, Japan.
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6
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Sánchez Á, Mengíbar M, Rivera-Rodríguez G, Moerchbacher B, Acosta N, Heras A. The effect of preparation processes on the physicochemical characteristics and antibacterial activity of chitooligosaccharides. Carbohydr Polym 2017; 157:251-257. [DOI: 10.1016/j.carbpol.2016.09.055] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/09/2016] [Accepted: 09/15/2016] [Indexed: 10/21/2022]
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7
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Alginate gels with a combination of calcium and chitosan oligomer mixtures as crosslinkers. Carbohydr Polym 2017; 156:490-497. [DOI: 10.1016/j.carbpol.2016.09.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/02/2016] [Accepted: 09/02/2016] [Indexed: 11/17/2022]
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8
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Mengíbar M, Mateos-Aparicio I, Miralles B, Heras A. Influence of the physico-chemical characteristics of chito-oligosaccharides (COS) on antioxidant activity. Carbohydr Polym 2013; 97:776-82. [PMID: 23911515 DOI: 10.1016/j.carbpol.2013.05.035] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 05/14/2013] [Accepted: 05/16/2013] [Indexed: 11/25/2022]
Abstract
Chito-oligosaccharides (COS) are being used as important functional materials for many applications due to their bioactivities. The aim of this research has been to assess the relationship between the physico-chemical characteristics, average molecular weight (Mw), acetylation degree (DA), polymerization degree (DP) and specially sequence composition determined by MALDI-TOF MS and the antioxidant properties of COS. These oligosaccharides were obtained by enzymatic depolymerization with chitosanase and lysozyme using a specific chitosan and its reacetylated product. The COS fraction below 5 kDa obtained from chitosanase depolymerization showed the highest capacity to scavenge DPPH radicals and to reduce Fe(3+). A correlation was found between the relative amount of molecules with a given A/D (acetylated vs deacetylated units) ratio within the COS and their antioxidant activity, which could be used to predict the antioxidant behavior of a fraction of chito-oligosaccharides.
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Affiliation(s)
- Marian Mengíbar
- Instituto de Estudios Biofuncionales, Dpto. Química Física II, Facultad de Farmacia, Universidad Complutense de Madrid, Pso. Juan XXIII, no. 1, 28040 Madrid, Spain
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9
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Heggset EB, Tuveng TR, Hoell IA, Liu Z, Eijsink VGH, Vårum KM. Mode of action of a family 75 chitosanase from Streptomyces avermitilis. Biomacromolecules 2012; 13:1733-41. [PMID: 22376136 DOI: 10.1021/bm201521h] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chitooligosaccharides (CHOS) are oligomers composed of glucosamine and N-acetylglucosamine with several interesting bioactivities that can be produced from enzymatic cleavage of chitosans. By controlling the degree of acetylation of the substrate chitosan, the enzyme, and the extent of enzyme degradation, CHOS preparations with limited variation in length and sequence can be produced. We here report on the degradation of chitosans with a novel family 75 chitosanase, SaCsn75A from Streptomyces avermitilis . By characterizing the CHOS preparations, we have obtained insight into the mode of action and subsite specificities of the enzyme. The degradation of a fully deacetylated and a 31% acetylated chitosan revealed that the enzyme degrade these substrates according to a nonprocessive, endo mode of action. With the 31% acetylated chitosan as substrate, the kinetics of the degradation showed an initial rapid phase, followed by a second slower phase. In the initial faster phase, an acetylated unit (A) is productively bound in subsite -1, whereas deacetylated units (D) are bound in the -2 subsite and the +1 subsite. In the slower second phase, D-units bind productively in the -1 subsite, probably with both acetylated and deacetylated units in the -2 subsite, but still with an absolute preference for deacetylated units in the +1 subsite. CHOS produced in the initial phase are composed of deacetylated units with an acetylated reducing end. In the slower second phase, higher amounts of low DP fully deacetylated oligomers (dimer and trimer) are produced, while the higher DP oligomers are dominated by compounds with acetylated reducing ends containing increasing amounts of internal acetylated units. The degradation of chitosans with varying degrees of acetylation to maximum extents of degradation showed that increasingly longer oligomers are produced with increasing degree of acetylation, and that the longer oligomers contain sequences of consecutive acetylated units interspaced by single deacetylated units. The catalytic properties of SaCsn75A differ from the properties of a previously characterized family 46 chitosanase from S. coelicolor (ScCsn46A).
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Affiliation(s)
- Ellinor B Heggset
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway
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10
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Heggset EB, Dybvik AI, Hoell IA, Norberg AL, Sørlie M, Eijsink VGH, Vårum KM. Degradation of chitosans with a family 46 chitosanase from Streptomyces coelicolor A3(2). Biomacromolecules 2011; 11:2487-97. [PMID: 20831280 DOI: 10.1021/bm1006745] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have studied the degradation of well-characterized soluble heteropolymeric chitosans by a novel family 46 chitosanase, ScCsn46A from Streptomyces coelicolor A3(2), to obtain insight into the enzyme's mode of action and to determine its potential for production of different chitooligosaccharides. The degradation of both a fully deacetylated chitosan and a 32% acetylated chitosan showed a continuum of oligomeric products and a rapid disappearance of the polymeric fraction, which is diagnostic for a nonprocessive endomode of action. The kinetics of the degradation of the 32% acetylated chitosan demonstrated an initial rapid phase and a slower second phase, in addition to a third and even slower kinetic phase. The first phase reflects the cleavage of the glycosidic linkage between two deacetylated units (D-D), the primary products being fully deacetylated dimers, trimers, and tetramers, as well as longer oligomers with increasing degrees of acetylation. In the subsequent slower kinetic phases, oligomers with a higher degree of acetylated units (A) appear, including oligomers with A's at the reducing or nonreducing end, which indicate that there are no absolute preferences for D in subsites -1 and +1. After maximum degradation of the chitosan, the dimers DA and DD were the dominant products. The degradation of chitosans with varying degrees of acetylation to a maximum degree of scission showed that ScCsn46A could degrade all chitosan substrates extensively, although to decreasing degrees of scission with increasing F(A). The potential use of ScCsn46A to prepare fully deacetylated oligomers and more highly acetylated oligomers from chitosan substrates with varying degrees of acetylation is discussed.
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Affiliation(s)
- Ellinor B Heggset
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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11
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Deters A, Petereit F, Schmidgall J, Hensel A. N-Acetyl-D-glucosamine oligosaccharides induce mucin secretion from colonic tissue and induce differentiation of human keratinocytes. J Pharm Pharmacol 2010; 60:197-204. [DOI: 10.1211/jpp.60.2.0008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Chitin oligosaccharides (DP2, DP3, DP4, DP5 and DP7) were investigated for their effects on epithelial cells and tissue (skin keratinocytes in-vitro and ex-vivo, and gastrointestinal epithelial membranes ex-vivo). Oligomers DP2, DP3 and DP5 at 10 μg mL−1 significantly stimulated the mitochondrial activity of cultured keratinocytes in-vitro (primary cells and HaCaT cell line), with highest activity observed for the pentamer (150% of untreated control). The effects were dose dependent. This higher energy status of primary cells was triggered into a higher differentiation status, as determined by the early and late differentiation markers keratins K1/K10 and involucrin, respectively. In contrast, increased mitogenic cell proliferation was not induced by the oligosaccharides. Toxic effects on keratinocytes were absent. Additionally for the first time a mucin-stimulating effect of chitin oligosaccharides DP3 and DP5 was observed in an ex-vivo model based on intestinal epithelial mucosa tissue. Mucin secretion was time dependent, leading to the secretion of polymers comparable to those normally secreted under physiological conditions. Mucin induction was observed from colonic tissue isolated from humans and pigs. Also, porcine stomach mucosa was stimulated by DP5, while ileum tissue reacted to only a minor extent. Potential developments towards products with wound-healing capacity and activity against chronic bowel disease are discussed.
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Affiliation(s)
- Alexandra Deters
- University of Münster, Institute for Pharmaceutical Biology and Phytochemistry, Hittorfstraße 56, D-48149 Münster, Germany
| | - Frank Petereit
- University of Münster, Institute for Pharmaceutical Biology and Phytochemistry, Hittorfstraße 56, D-48149 Münster, Germany
| | - Jörg Schmidgall
- University of Münster, Institute for Pharmaceutical Biology and Phytochemistry, Hittorfstraße 56, D-48149 Münster, Germany
| | - Andreas Hensel
- University of Münster, Institute for Pharmaceutical Biology and Phytochemistry, Hittorfstraße 56, D-48149 Münster, Germany
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12
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Heggset EB, Hoell IA, Kristoffersen M, Eijsink VGH, Vårum KM. Degradation of chitosans with chitinase G from Streptomyces coelicolor A3(2): production of chito-oligosaccharides and insight into subsite specificities. Biomacromolecules 2010; 10:892-9. [PMID: 19222164 DOI: 10.1021/bm801418p] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have studied the degradation of soluble heteropolymeric chitosans with a bacterial family 19 chitinase, ChiG from Streptomyces coelicolor A3(2), to obtain insight into the mode of action of ChiG, to determine subsite preferences for acetylated and deacetylated sugar units, and to evaluate the potential of ChiG for production of chito-oligosaccharides. Degradation of chitosans with varying degrees of acetylation was followed using NMR for the identity (acetylated/deacetylated) of new reducing and nonreducing ends as well as their nearest neighbors and using gel filtration to analyze the size distribution of the oligomeric products. Degradation of a 64% acetylated chitosan yielded a continuum of oligomers, showing that ChiG operates according to a nonprocessive, endo mode of action. The kinetics of the degradation showed an initial rapid phase dominated by cleavage of three consecutive acetylated units (A; occupying subsites -2, -1, and +1), and a slower kinetic phase reflecting the cleavage of the glycosidic linkage between a deacetylated unit (D, occupying subsite -1) and an A (occupying subsite +1). Characterization of isolated oligomer fractions obtained at the end of the initial rapid phase and at the end of the slower kinetic phase confirmed the preference for A binding in subsites -2, -1, and +1 and showed that oligomers with a deacetylated reducing end appeared only during the second kinetic phase. After maximum conversion of the chitosan, the dimers AD/AA and the trimer AAD were the dominating products. Degradation of chitosans with varying degrees of acetylation to maximum degree of scission produced a wide variety of oligomer mixtures, differing in chain length and composition of acetylated/deacetylated units. These results provide insight into the properties of bacterial family 19 chitinases and show how these enzymes may be used to convert chitosans to several types of chito-oligosaccharide mixtures.
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Affiliation(s)
- Ellinor B Heggset
- Norwegian Biopolymer Laboratory, Department of Biotechnology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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Synthesis, structural characterization and properties of water-soluble N-(γ-propanoyl-amino acid)-chitosans. Carbohydr Polym 2008. [DOI: 10.1016/j.carbpol.2007.05.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Psylinakis E, Boneca IG, Mavromatis K, Deli A, Hayhurst E, Foster SJ, Vårum KM, Bouriotis V. Peptidoglycan N-acetylglucosamine deacetylases from Bacillus cereus, highly conserved proteins in Bacillus anthracis. J Biol Chem 2005; 280:30856-63. [PMID: 15961396 DOI: 10.1074/jbc.m407426200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The genomes of Bacillus cereus and its closest relative Bacillus anthracis contain 10 polysaccharide deacetylase homologues. Six of these homologues have been proposed to be peptidoglycan N-acetylglucosamine deacetylases. Two of these genes, namely bc1960 and bc3618, have been cloned and expressed in Escherichia coli, and the recombinant enzymes have been purified to homogeneity and further characterized. Both enzymes were effective in deacetylating cell wall peptidoglycan from the Gram(+) Bacillus cereus and Bacillus subtilis and the Gram(-) Helicobacter pylori as well as soluble chitin substrates and N-acetylchitooligomers. However, the enzymes were not active on acetylated xylan. These results provide insight into the substrate specificity of carbohydrate esterase family 4 enzymes. It was revealed that both enzymes deacetylated only the GlcNAc residue of the synthetic muropeptide N-acetyl-D-glucosamine-(beta-1,4)-N-acetylmuramyl-L-alanine-D-isoglutamine. Analysis of the constituent muropeptides of peptidoglycan from B. subtilis and H. pylori resulting from incubation of the enzymes BC1960 and BC3618 with these polymers and subsequent hydrolysis by Cellosyl and mutanolysin, respectively, similarly revealed that both enzymes deacetylate GlcNAc residues of peptidoglycan. Kinetic analysis toward GlcNAc(2-6) revealed that GlcNAc4 was the favorable substrate for both enzymes. Identification of the sequence of N-acetychitooligosaccharides (GlcNAc(2-4)) following enzymatic deacetylation by using 1H NMR revealed that both enzymes deacetylate all GlcNAc residues of the oligomers except the reducing end ones. Enzymatic deacetylation of chemically acetylated vegetative peptidoglycan from B. cereus by BC1960 and BC3618 resulted in increased resistance to lysozyme digestion. This is the first biochemical study of bacterial peptidoglycan N-acetylglucosamine deacetylases.
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Affiliation(s)
- Emmanuel Psylinakis
- Department of Biology, Enzyme Biotechnology Group, University of Crete, P.O. Box 2208, Vasilika Vouton 714 09, Heraklion, Crete, Greece
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15
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Sørbotten A, Horn SJ, Eijsink VGH, Vårum KM. Degradation of chitosans with chitinase B from Serratia marcescens. FEBS J 2004; 272:538-49. [PMID: 15654891 DOI: 10.1111/j.1742-4658.2004.04495.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Family 18 chitinases such as chitinase B (ChiB) from Serratia marcescens catalyze glycoside hydrolysis via a mechanism involving the N-acetyl group of the sugar bound to the -1 subsite. We have studied the degradation of the soluble heteropolymer chitosan, to obtain further insight into catalysis in ChiB and to experimentally assess the proposed processive action of this enzyme. Degradation of chitosans with varying degrees of acetylation was monitored by following the size-distribution of oligomers, and oligomers were isolated and partly sequenced using (1)H-NMR spectroscopy. Degradation of a chitosan with 65% acetylated units showed that ChiB is an exo-enzyme which degrades the polymer chains from their nonreducing ends. The degradation showed biphasic kinetics: the faster phase is dominated by cleavage on the reducing side of two acetylated units (occupying subsites -2 and -1), while the slower kinetic phase reflects cleavage on the reducing side of a deacetylated and an acetylated unit (bound to subsites -2 and -1, respectively). The enzyme did not show preferences with respect to acetylation of the sugar bound in the +1 subsite. Thus, the preference for an acetylated unit is absolute in the -1 subsite, whereas substrate specificity is less stringent in the -2 and +1 subsites. Consequently, even chitosans with low degrees of acetylation could be degraded by ChiB, permitting the production of mixtures of oligosaccharides with different size distributions and chemical composition. Initially, the degradation of the 65% acetylated chitosan almost exclusively yielded oligomers with even-numbered chain lengths. This provides experimental evidence for a processive mode of action, moving the sugar chain two residues at a time. The results show that nonproductive binding events are not necessarily followed by substrate release but rather by consecutive relocations of the sugar chain.
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Affiliation(s)
- Audun Sørbotten
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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16
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Holme H, Foros H, Pettersen H, Dornish M, Smidsrød O. Thermal depolymerization of chitosan chloride. Carbohydr Polym 2001. [DOI: 10.1016/s0144-8617(00)00332-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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17
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18
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Tømmeraas K, Vårum KM, Christensen BE, Smidsrød O. Preparation and characterisation of oligosaccharides produced by nitrous acid depolymerisation of chitosans. Carbohydr Res 2001; 333:137-44. [PMID: 11448674 DOI: 10.1016/s0008-6215(01)00130-6] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Two chitosans with widely different chemical composition (fraction of N-acetylated units (F(A))<0.001 and F(A)=0.59), were degraded by nitrous acid, to obtain the reactive 2,5-anhydro-D-mannose- (M-) unit at the new reducing end. The fully N-acetylated and fully N-deacetylated oligomers were separated by size-exclusion chromatography. Both the chemical structure and purity were studied by one- and two-dimensional 1H and 13C NMR methods. The fully N-acetylated oligomers were found to be stable, whereas the N-deacetylated oligomers reacted intermolecularly by a Schiff base reaction between the 2-amino group on the N-deacetylated units and the M-units, facilitating the cleavage of the glycosidic bond next to the M-unit and the formation of 5-hydroxymethylfurfural (HMF).
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Affiliation(s)
- K Tømmeraas
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology, Norwegian University of Science and Technology (NTNU), N-7491, Trondheim, Norway.
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Vårum KM, Holme HK, Izume M, Stokke BT, Smidsrød O. Determination of enzymatic hydrolysis specificity of partially N-acetylated chitosans. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1291:5-15. [PMID: 8781519 DOI: 10.1016/0304-4165(96)00038-4] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A new method for determining the specificity of hydrolysis of the linear binary heteropolysaccharide chitosan composed of (1-->4)-linked 2-acetamido-2-deoxy-beta-D-glucopyranose (GlcNAc; A-unit) and 2-amino-2-deoxy-beta-D-glucopyranose (GlcN; D-unit) residues is described. The method is based on the assignments of the 13C chemical shifts of the identity (A- or D-units) of the new reducing and non-reducing ends and the variation in their nearest neighbours, using low molecular weight chitosans with known random distribution of A- and D-units as substrate. A highly N-acetylated chitosan with fraction of acetylated units (FA) of 0.68 and a number-average degree of polymerization (DPn) of 30 was hydrolysed with hen egg-white lysozyme, showing that both the new reducing and non-reducing ends consisted exclusively of A-units, indicating a high specificity for A-units in subsites DL and EL on lysozyme. Our data suggests that the preceding unit of the reducing A-units, is invariable, and based on earlier studies, most probably an A-unit, while the unit following the non-reducing A-units can be either an A- or a D-unit. A more detailed study of the specificity of lysozyme at subsite DL was performed by hydrolyzing a more deacetylated chitosan (FA = 0.35 and DPn of 20) to a DPn of 9, showing that even for this chitosan more than 90% of the new reducing ends were acetylated units. Thus, lysozyme depolymerizes partially N-acetylated chitosans by preferentially hydrolyzing sequences of acetylated units bound to site CL, DL and EL of the active cleft, while there is no specificity between acetylated and deacetylated units to site FL. In addition, a moderately N-acetylated chitosan with fraction of acetylated units (FA) of 0.35 and a DPn of 20 was hydrolysed with Bacillus sp. No. 7-M chitosanase, showing that both the new reducing and non-reducing ends consisted exclusively of D-units. Our data suggests that the nearest neigbour to the D-unit at the reducing end is invariable, and based on earlier studies, most probably a D-unit, while the unit following the non-reducing D-units can be either an A- or a D-unit. We conclude that the Bacillus chitosanase hydrolyzes partially N-acetylated chitosan by preferentially attacking sequences of three consecutive deacetylated units, hypothetical subsites CC, DC and EC, where the cleavage occur between sugar units bound to subsites DC and EC. A hypothetical subsite FC on the chitosanase show no specificity with respect to A- and D-units. The new NMR method described herein offers a time and labour-saving alternative to the procedure of extensive hydrolysis of the binary heteropolysaccharide chitosan and subsequent isolation and characterization of the oligosaccharides.
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Affiliation(s)
- K M Vårum
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway.
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Kristiansen A, Vårum KM, Grasdalen H. Competitive binding of highly de-N-acetylated chitosans and N,N'-diacetylchitobiose to lysozyme from chicken egg white studied by 1H NMR spectroscopy. Carbohydr Res 1996; 289:143-50. [PMID: 8805778 DOI: 10.1016/0008-6215(96)00109-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- A Kristiansen
- Norwegian Biopolymer Laboratory, Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway
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Stokke BT, Vårum KM, Holme HK, Hjerde RJ, Smidsrød O. Sequence specificities for lysozyme depolymerization of partially N-acetylated chitosans. CAN J CHEM 1995. [DOI: 10.1139/v95-244] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The influence of sugar residue sequence in partially N-acetylated chitosans on relative hydrolysis rate catalyzed by lysozyme was studied. The relative rates were modelled assuming an Arrhenius-type relation for the relative rate constants. The apparent activation energy was assumed to consist of additive contributions from GlcN or GlcNAc residues within the polymer chain interacting with sites A–F of the active cleft of lysozyme. This model accounted well for the relative hydrolysis rates reported for well-defined oligomers. Calculated and experimental data for the dependence of the initial relative hydrolysis rates on fraction of acetylated units, FA, showed an FA3,6 dependence. A fully water-soluble highly N-acetylated chitosan with FA = 0.68 was depolymerized using lysozyme for further testing of the model. Analyses of the 13C nuclear magnetic resonance spectra of the diad sequences at the new reducing and nonreducing ends formed by lysozyme showed that this enzymatic depolymerization was dominated by chitosan sequences presenting GlcNAc residues to sites C, D, and E of the active cleft. In contrast, there was no selectivity between GlcNAc and GlcN residues interacting with site F. These selectivities were confirmed by the calculated contributions to the apparent activation energy of these sites. The experimentally determined depletion in the diad and triad frequencies of GlcNAc during the course of lysozyme hydrolysis was in good agreement with the model calculations. Keywords: lysozyme, chitosan, chitin, sequence specificity, subsite model.
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