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Qin X, Xin Y, Su X, Wang X, Zhang J, Tu T, Wang Y, Yao B, Huang H, Luo H. Heterologous expression and characterization of thermostable chitinase and β-N-acetylhexosaminidase from Caldicellulosiruptor acetigenus and their synergistic action on the bioconversion of chitin into N-acetyl-d-glucosamine. Int J Biol Macromol 2021; 192:250-257. [PMID: 34627844 DOI: 10.1016/j.ijbiomac.2021.09.204] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 09/29/2021] [Accepted: 09/29/2021] [Indexed: 11/30/2022]
Abstract
The bioconversion of chitin into N-acetyl-d-glucosamine (GlcNAc) using chitinolytic enzymes is one of the important avenues for chitin valorization. However, industrial applications of chitinolytic enzymes have been limited by their poor thermostability. Therefore, it is necessary to discover thermostable chitinolytic enzymes for GlcNAc production from chitin. In this study, two chitinolytic enzyme-encoding genes CaChiT and CaHex from Caldicellulosiruptor acetigenus were identified and heterologously expressed in Escherichia coli. The purified recombinant CaChiT and CaHex showed optimal activities at 70 °C and 90 °C respectively, and exhibited good thermostability over a range of temperature below 70 °C and broad pH stability at pH range of 3.0-8.0. CaChiT and CaHex were active on colloidal chitin, pNP-(GlcNAc)2, pNP-(GlcNAc)3, and pNP-GlcNAc, pNP-(GlcNAc)2, pNP-(GlcNAc)3, pNP-Glc respectively. Besides, the chitin oligosaccharides and colloidal chitin hydrolysis profiles revealed that CaChiT degraded chitin chains through exo-mode of action. Furthermore, CaChiT and CaHex exhibited a synergistic effect in the degradation of colloidal chitin, reaching 0.60 mg/mL of GlcNAc production after 1 h incubation. These results suggested that a combination of CaChiT and CaHex have great potential for industrial applications in the enzymatic production of GlcNAc from chitin-containing biowastes.
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Affiliation(s)
- Xing Qin
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - YanZhe Xin
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiaoyun Su
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiaolu Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Jie Zhang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Tao Tu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yaru Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Bin Yao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Huoqing Huang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Huiying Luo
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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Taira T, Gushiken C, Sugata K, Ohnuma T, Fukamizo T. Unique GH18 chitinase from Euglena gracilis: full-length cDNA cloning and characterization of its catalytic domain. Biosci Biotechnol Biochem 2018; 82:1090-1100. [PMID: 29621939 DOI: 10.1080/09168451.2018.1459463] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A cDNA of putative chitinase from Euglena gracilis, designated EgChiA, encoded 960 amino acid residues, which is arranged from N-terminus in the order of signal peptide, glycoside hydrolase family 18 (GH18) domain, carbohydrate binding module family 18 (CBM18) domain, GH18 domain, CBM18 domain, and transmembrane helix. It is likely that EgChiA is anchored on the cell surface. The recombinant second GH18 domain of EgChiA, designated as CatD2, displayed optimal catalytic activity at pH 3.0 and 50 °C. The lower the polymerization degree of the chitin oligosaccharides [(GlcNAc)4-6] used as the substrates, the higher was the rate of degradation by CatD2. CatD2 degraded chitin nanofibers as an insoluble substrate, and it produced only (GlcNAc)2 and GlcNAc. Therefore, we speculated that EgChiA localizes to the cell surface of E. gracilis and is involved in degradation of chitin polymers into (GlcNAc)2 or GlcNAc, which are easily taken up by the cells.
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Affiliation(s)
- Toki Taira
- a Department of Bioscience and Biotechnology , University of the Ryukyus , Okinawa , Japan
| | - Chika Gushiken
- a Department of Bioscience and Biotechnology , University of the Ryukyus , Okinawa , Japan
| | - Kobeni Sugata
- a Department of Bioscience and Biotechnology , University of the Ryukyus , Okinawa , Japan
| | - Takayuki Ohnuma
- b Department of Advanced Bioscience , Kinki University , Nara , Japan
| | - Tamo Fukamizo
- b Department of Advanced Bioscience , Kinki University , Nara , Japan
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3
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Abstract
The early detection of many human diseases is crucial if they are to be treated successfully. Therefore, the development of imaging techniques that can facilitate early detection of disease is of high importance. Changes in the levels of enzyme expression are known to occur in many diseases, making their accurate detection at low concentrations an area of considerable active research. Activatable fluorescent probes show immense promise in this area. If properly designed they should exhibit no signal until they interact with their target enzyme, reducing the level of background fluorescence and potentially endowing them with greater sensitivity. The mechanisms of fluorescence changes in activatable probes vary. This review aims to survey the field of activatable probes, focusing on their mechanisms of action as well as illustrating some of the in vitro and in vivo settings in which they have been employed.
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Affiliation(s)
- Christopher R Drake
- Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, Box 0946, San Francisco, CA, 94107, USA
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Horn SJ, Sørlie M, Vaaje-Kolstad G, Norberg AL, Synstad B, Vårum KM, Eijsink VGH. Comparative studies of chitinases A, B and C fromSerratia marcescens. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.1080/10242420500518482] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Krokeide IM, Synstad B, Gåseidnes S, Horn SJ, Eijsink VGH, Sørlie M. Natural substrate assay for chitinases using high-performance liquid chromatography: A comparison with existing assays. Anal Biochem 2007; 363:128-34. [PMID: 17288981 DOI: 10.1016/j.ab.2006.12.044] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Revised: 11/27/2006] [Accepted: 12/28/2006] [Indexed: 10/23/2022]
Abstract
The determination of kinetic parameters of chitinases using natural substrates is difficult due to low K(m) values, which require the use of low substrate concentrations that are hard to measure. Using the natural substrate (GlcNAc)(4), we have developed an assay for the determination of k(cat) and K(m)values of chitinases. Product concentrations as low as 0.5 microM were detected using normal-phase high-performance liquid chromatography (HPLC) with an amide 80 column (0.20 x 25 cm) using spectrophotometric detection at 210 nm. By means of this assay, k(cat) and K(m)values for chitinases A (ChiA) and B (ChiB) of Serratia marcescens were found to be 33+/-1s(-1) and 9+/-1 microM and 28+/-2s(-1) and 4+/-2 microM, respectively. For ChiB, these values were compared to those found with commonly used substrates where the leaving group is a (nonnatural) chromophore, revealing considerable differences. For example, assays with 4-methylumbelliferyl-(GlcNAc)(2) yielded a k(cat) value of 18+/-2s(-1) and a K(m) value of 30+/-6 microM. For two ChiB mutants containing a Trp --> Ala mutation in the +1 or +2 subsites, the natural substrate and the 4-methylumbelliferyl-(GlcNAc)(2) assays yielded rather similar K(m) values (5-fold difference at most) but showed dramatic differences in k(cat) values (up to 90-fold). These results illustrate the risk of using artificial substrates for characterization of chitinases and, thus, show that the new HPLC-based assay is a valuable tool for future chitinase research.
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Affiliation(s)
- Inger-Mari Krokeide
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Aas, Norway
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Kobayashi A, Kuwata H, Kohri M, Izumi R, Watanabe T, Shoda S. A Bacterial Chitinase Acts as Catalyst for Synthesis of theN‐Linked Oligosaccharide Core Trisaccharide by Employing a Sugar Oxazoline Substrate. J Carbohydr Chem 2007. [DOI: 10.1080/07328300600966448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Atsushi Kobayashi
- a Department of Biomolecular Engineering , Graduate School of Engineering, Tohoku University , Sendai, Japan
| | - Hideyuki Kuwata
- a Department of Biomolecular Engineering , Graduate School of Engineering, Tohoku University , Sendai, Japan
| | - Michinari Kohri
- a Department of Biomolecular Engineering , Graduate School of Engineering, Tohoku University , Sendai, Japan
| | - Ryuko Izumi
- a Department of Biomolecular Engineering , Graduate School of Engineering, Tohoku University , Sendai, Japan
| | - Takeshi Watanabe
- b Department of Applied Biological Chemistry , Niigata University , Niigata, Japan
| | - Shin‐ichiro Shoda
- a Department of Biomolecular Engineering , Graduate School of Engineering, Tohoku University , Sendai, Japan
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Kohri M, Kobayashi A, Shoda SI. Design and Utilization of Chitinases with Low Hydrolytic Activities. TRENDS GLYCOSCI GLYC 2007. [DOI: 10.4052/tigg.19.165] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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8
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Eneyskaya EV, Ivanen DR, Bobrov KS, Isaeva-Ivanova LS, Shabalin KA, Savel'ev AN, Golubev AM, Kulminskaya AA. Biochemical and kinetic analysis of the GH3 family β-xylosidase from Aspergillus awamori X-100. Arch Biochem Biophys 2007; 457:225-34. [PMID: 17145041 DOI: 10.1016/j.abb.2006.10.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 10/20/2006] [Accepted: 10/22/2006] [Indexed: 11/30/2022]
Abstract
The beta-xylosidase from Aspergillus awamori X-100 belonging to the family 3 glycoside hydrolase revealed a distinctive transglycosylating ability to produce xylooligosaccharides with degree of polymerization more than 7. In order to explain this fact, the enzyme has been subjected to the detailed biochemical study. The enzymatic hydrolysis of p-nitrophenyl beta-D-xylopyranoside was found to occur with overall retention of substrate anomeric configuration suggesting cleavage of xylosidic bonds through a double-displacement mechanism. Kinetic study with aryl beta-xylopyranosides substrates, in which leaving group pK(a)s were in the range of 3.96-10.32, revealed monotonic function of log(k(cat)) and no correlation of log(k(cat)/Km) versus pKa values indicating deglycosylation as a rate-limiting step for the enzymatic hydrolysis. The classical bell-shaped pH dependence of k(cat)/Km indicated two ionizable groups in the beta-xylosidase active site with apparent pKa values of 2.2 and 6.4. The kinetic parameters of hydrolysis, Km and k(cat), of p-nitrophenyl beta-D-1,4-xylooligosaccharides were very close to those for hydrolysis of p-nitrophenyl-beta-D-xylopyranoside. Increase of p-nitrophenyl-beta-D-xylopyranoside concentration up to 80 mM led to increasing of the reaction velocity resulting in k(cat)(app)=81 s(-1). Addition of alpha-methyl D-xylopyranoside to the reaction mixture at high concentration of p-nitrophenyl-beta-D-xylopyranoside (50 mM) caused an acceleration of the beta-xylosidase-catalyzed reactions and appearance of a new transglycosylation product, alpha-methyl D-xylopyranosyl-1,4-beta-D-xylopyranoside, that was identified by 1H NMR spectroscopy. The kinetic model suggested for the enzymatic reaction was consistent with the results obtained.
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Affiliation(s)
- Elena V Eneyskaya
- Petersburg Nuclear Physics Institute, Russian Academy of Science, Molecular and Radiation Biology Division, Gatchina 188300, Russia
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Boer H, Simolin H, Cottaz S, Söderlund H, Koivula A. Heterologous expression and site-directed mutagenesis studies of two Trichoderma harzianum chitinases, Chit33 and Chit42, in Escherichia coli. Protein Expr Purif 2006; 51:216-26. [PMID: 16997574 DOI: 10.1016/j.pep.2006.07.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 07/26/2006] [Accepted: 07/27/2006] [Indexed: 10/24/2022]
Abstract
Heterologous expression of two fungal chitinases, Chit33 and Chit42, from Trichoderma harzianum was tested in the different compartments and on the surface of Escherichia coli cells. Our goal was to find a fast and efficient expression system for protein engineering and directed evolution studies of the two fungal enzymes. Cytoplasmic overexpression resulted in both cases in inclusion body formation, where active enzyme could be recovered after refolding. Periplasmic expression of Chit33, and especially of Chit42, proved to be better suited for mutagenesis purposes. Recombinant chitinases from the periplasmic expression system showed activity profiles similar to those of the native proteins. Both chitinases also degraded a RET (resonance energy transfer) based bifunctionalized chitinpentaose substrate in a similar manner as reported for some putative exochitinases in the glycosyl hydrolase family 18, offering a sensitive way to assay their activities. We further demonstrated that Chit42 can also be displayed on E. coli surface and the enzymatic activity can be measured directly from the whole cells using methylumbelliferyl-chitinbioside as a substrate. The periplasmic expression and the surface display of Chit42, both offer a suitable expression system for protein engineering and activity screening in a microtiter plate scale. As a first mutagenesis approach we verified the essential role of the two carboxylic acid residues E172 (putative proton donor) and D170 (putative stabilizer) in the catalytic mechanism of Chit42, and additionally the role of the carboxylic acid E145 (putative proton donor) in the catalytic mechanism of Chit33.
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Affiliation(s)
- Harry Boer
- VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Finland.
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10
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Horn SJ, Sørbotten A, Synstad B, Sikorski P, Sørlie M, Vårum KM, Eijsink VGH. Endo/exo mechanism and processivity of family 18 chitinases produced by Serratia marcescens. FEBS J 2006; 273:491-503. [PMID: 16420473 DOI: 10.1111/j.1742-4658.2005.05079.x] [Citation(s) in RCA: 206] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We present a comparative study of ChiA, ChiB, and ChiC, the three family 18 chitinases produced by Serratia marcescens. All three enzymes eventually converted chitin to N-acetylglucosamine dimers (GlcNAc2) and a minor fraction of monomers. ChiC differed from ChiA and ChiB in that it initially produced longer oligosaccharides from chitin and had lower activity towards an oligomeric substrate, GlcNAc6. ChiA and ChiB could convert GlcNAc6 directly to three dimers, whereas ChiC produced equal amounts of tetramers and dimers, suggesting that the former two enzymes can act processively. Further insight was obtained by studying degradation of the soluble, partly deacetylated chitin-derivative chitosan. Because there exist nonproductive binding modes for this substrate, it was possible to discriminate between independent binding events and processive binding events. In reactions with ChiA and ChiB the polymer disappeared very slowly, while the initially produced oligomers almost exclusively had even-numbered chain lengths in the 2-12 range. This demonstrates a processive mode of action in which the substrate chain moves by two sugar units at a time, regardless of whether complexes formed along the way are productive. In contrast, reactions with ChiC showed rapid disappearance of the polymer and production of a continuum of odd- and even-numbered oligomers. These results are discussed in the light of recent literature data on directionality and synergistic effects of ChiA, ChiB and ChiC, leading to the conclusion that ChiA and ChiB are processive chitinases that degrade chitin chains in opposite directions, while ChiC is a nonprocessive endochitinase.
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Affiliation(s)
- Svein J Horn
- Department of Chemistry, Biotechnology and Food Science, the Norwegian University of Life Sciences, As, Norway
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11
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Murata T, Amarume S, Hattori T, Tokuyama S, Tokuyasu K, Kawagishi H, Usui T. Purification and characterization of a chitinase from Amycolatopsis orientalis with N-acetyllactosamine-repeating unit releasing activity. Biochem Biophys Res Commun 2005; 336:514-20. [PMID: 16143301 DOI: 10.1016/j.bbrc.2005.08.123] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Accepted: 08/17/2005] [Indexed: 11/25/2022]
Abstract
We report a novel enzyme from the culture filtrate of Amycolatopsis orientalis, that endoglycosidically releases an N-acetyllactosamine-repeating unit (Galbeta1,4GlcNAcbeta1,3Galbeta1,4GlcNAc, LN2) from a synthetic chromogenic substrate Galbeta1,4GlcNAcbeta1,3Galbeta1,4GlcNAcbeta-pNP (1). The enzyme activity was purified by 80% saturated ammonium sulfate precipitation followed by gel filtration and affinity chromatography. The enzyme splits 1, Galbeta1,4GlcNAcbeta-pNP (2), GlcNAcbeta1,3Galbeta1,4GlcNAcbeta-pNP (3), and GlcNAcbeta1,4GlcNAcbeta-pNP (4) into the corresponding oligosaccharides and p-nitrophenol. The catalytic efficiencies (k(cat)/K(m)) for compounds 1, 2, and 4 were 0.6, 0.05, and 13, respectively. Compound 4 acts as a fairly good substrate for the enzyme, and LN2-releasing activity was inhibited by 4 and GlcNAcbeta1,4GlcNAcbeta1,4GlcNAcbeta-pNP (7), indicating that this enzyme activity is derived from a kind of chitinase. The enzyme hydrolyzed 1 by a mechanism leading to retention of the anomeric configuration. This is the first report of a N-acetyllactosamine-repeating unit releasing enzyme.
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Affiliation(s)
- Takeomi Murata
- Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.
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12
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Eneyskaya EV, Ivanen DR, Shabalin KA, Kulminskaya AA, Backinowsky LV, Brumer Iii H, Neustroev KN. Chemo-enzymatic synthesis of 4-methylumbelliferyl β-(1→4)-d-xylooligosides: new substrates for β-d-xylanase assays. Org Biomol Chem 2005; 3:146-51. [PMID: 15602610 DOI: 10.1039/b409583a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Transglycosylation catalyzed by a beta-D-xylosidase from Aspergillus sp. was used to synthesize a set of 4-methylumbelliferyl (MU) beta-1-->4-D-xylooligosides having the common structure [beta-D-Xyl-(1-->4)]2-5-beta-D-Xyl-MU. MU xylobioside synthesized chemically by the condensation of protected MU beta-D-xylopyranoside with ethyl 2,3,4-tri-O-acetyl-1-thio-beta-D-xylopyranoside was used as a substrate for transglycosylation with the beta-D-xylosidase from Aspergillus sp. to produce higher MU xylooligosides. The structures of oligosaccharides obtained were established by 1H and 13C NMR spectroscopy and electrospray tandem mass spectrometry. MU beta-D-xylooligosides synthesized were tested as fluorogenic substrates for the GH-10 family beta-D-xylanase from Aspergillus orizae and the GH-11 family beta-D-xylanase I from Trichoderma reesei. Both xylanases released the aglycone from MU xylobioside and the corresponding trioside. With substrates having d.p. 4 and 5, the enzymes manifested endolytic activities, splitting off MU, MUX, and MUX2 primarily.
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Affiliation(s)
- Elena V Eneyskaya
- Petersburg Nuclear Physics Institute, Russian Academy of Science, Molecular and Radiation Biology Division, Gatchina, 188300, Russia
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Honda Y, Kitaoka M, Tokuyasu K, Hayashi K. Reaction Mechanism of Chitinase Belonging to Glycosidase Family 18. J Appl Glycosci (1999) 2004. [DOI: 10.5458/jag.51.155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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14
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Borriss R, Krah M, Brumer H, Kerzhner MA, Ivanen DR, Eneyskaya EV, Elyakova LA, Shishlyannikov SM, Shabalin KA, Neustroev KN. Enzymatic synthesis of 4-methylumbelliferyl (1-->3)-beta-D-glucooligosaccharides-new substrates for beta-1,3-1,4-D-glucanase. Carbohydr Res 2003; 338:1455-67. [PMID: 12829391 DOI: 10.1016/s0008-6215(03)00199-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The transglycosylation reactions catalyzed by beta-1,3-D-glucanases (laminaranases) were used to synthesize a number of 4-methylumbelliferyl (MeUmb) (1-->3)-beta-D-gluco-oligosaccharides having the common structure [beta-D-Glcp-(1-->3)](n)-beta-D-Glcp-MeUmb, where n=1-5. The beta-1,3-D-glucanases used were purified from the culture liquid of Oerskovia sp. and from a homogenate of the marine mollusc Spisula sachalinensis. Laminaran and curdlan were used as (1-->3)-beta-D-glucan donor substrates, while MeUmb-beta-D-glucoside (MeUmbGlcp) was employed as a transglycosylation acceptor. Modification of [beta-D-Glcp-(1-->3)](2)-beta-D-Glcp-MeUmb (MeUmbG(3)) gives 4,6-O-benzylidene-D-glucopyranosyl or 4,6-O-ethylidene-D-glucopyranosyl groups at the non-reducing end of artificial oligosaccharides. The structures of all oligosaccharides obtained were solved by 1H and 13C NMR spectroscopy and electrospray tandem mass spectrometry. The synthetic oligosaccharides were shown to be substrates for a beta-1,3-1,4-D-glucanase from Rhodothermus marinus, which releases MeUmb from beta-di- and beta-triglucosides and from acetal-protected beta-triglucosides. When acting upon substrates with d.p.>3, the enzyme exhibits an endolytic activity, primarily cleaving off MeUmbGlcp and MeUmbG(2).
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Affiliation(s)
- Rainer Borriss
- AG Bakteriengenetik, Institut fur Biologie, Humboldt Universität Berlin Chausseestrasse 117, D-10115 Berlin, Germany
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15
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Tanaka T, Fukui T, Imanaka T. Different cleavage specificities of the dual catalytic domains in chitinase from the hyperthermophilic archaeon Thermococcus kodakaraensis KOD1. J Biol Chem 2001; 276:35629-35. [PMID: 11468293 DOI: 10.1074/jbc.m105919200] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The chitinase from the hyperthermophilic archaeon Thermococcus kodakaraensis KOD1, Tk-ChiA, has an interesting multidomain structure containing dual catalytic domains and triple chitin-binding domains. To determine the biochemical properties of each domain, we constructed deletion mutant genes corresponding to the individual catalytic domains and purified the recombinant proteins. A synergistic effect was observed when chitin was degraded in the presence of both catalytic domains, suggesting different cleavage specificity of these domains. Analyses of degradation products from N-acetyl-chitooligosaccharides and their chromogenic derivatives with thin layer chromatography indicated that the N-terminal catalytic domain mainly hydrolyzed the second glycosidic bond from the nonreducing end of the oligomers, whereas the C-terminal domain randomly hydrolyzed glycosidic bonds other than the first bond from the nonreducing end. Both catalytic domains formed diacetyl-chitobiose as a major end product and possessed transglycosylation activity. Further analysis of degradation products from colloidal chitin with high performance liquid chromatography showed that the N-terminal catalytic domain exclusively liberated diacetyl-chitobiose, whereas reactions with the C-terminal domain led to N-acetyl-chitooligosaccharides of various lengths. These results demonstrated that the N-terminal and C-terminal catalytic domains functioned as exo- and endochitinases, respectively. The biochemical results provide a physiological explanation for the presence of two catalytic domains with different specificity and suggest a cooperative function between the two on a single polypeptide in the degradation of chitin.
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Affiliation(s)
- T Tanaka
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
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16
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van Aalten DM, Komander D, Synstad B, Gåseidnes S, Peter MG, Eijsink VG. Structural insights into the catalytic mechanism of a family 18 exo-chitinase. Proc Natl Acad Sci U S A 2001; 98:8979-84. [PMID: 11481469 PMCID: PMC55359 DOI: 10.1073/pnas.151103798] [Citation(s) in RCA: 334] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Chitinase B (ChiB) from Serratia marcescens is a family 18 exo-chitinase whose catalytic domain has a TIM-barrel fold with a tunnel-shaped active site. We have solved structures of three ChiB complexes that reveal details of substrate binding, substrate-assisted catalysis, and product displacement. The structure of an inactive ChiB mutant (E144Q) complexed with a pentameric substrate (binding in subsites -2 to +3) shows closure of the "roof" of the active site tunnel. It also shows that the sugar in the -1 position is distorted to a boat conformation, thus providing structural evidence in support of a previously proposed catalytic mechanism. The structures of the active enzyme complexed to allosamidin (an analogue of a proposed reaction intermediate) and of the active enzyme soaked with pentameric substrate show events after cleavage of the glycosidic bond. The latter structure shows reopening of the roof of the active site tunnel and enzyme-assisted product displacement in the +1 and +2 sites, allowing a water molecule to approach the reaction center. Catalysis is accompanied by correlated structural changes in the core of the TIM barrel that involve conserved polar residues whose functions were hitherto unknown. These changes simultaneously contribute to stabilization of the reaction intermediate and alternation of the pKa of the catalytic acid during the catalytic cycle.
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Affiliation(s)
- D M van Aalten
- Wellcome Trust Biocentre, Department of Biochemistry, University of Dundee, Dundee DD1 5EH, Scotland.
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Fukamizo T, Sasaki C, Schelp E, Bortone K, Robertus JD. Kinetic properties of chitinase-1 from the fungal pathogen Coccidioides immitis. Biochemistry 2001; 40:2448-54. [PMID: 11327866 DOI: 10.1021/bi001537s] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The endochitinase from Coccidioides immitis (CiX1) is a member of the class 18 chitinase family. Here we show the enzyme functions by a retaining catalytic mechanism; that is, the beta-conformation of the chitin substrate linkages is preserved after hydrolysis. The pattern of cleavage of N-acetyglucosamine (GlcNAc) oligosaccharide substrates has been determined. (GlcNAc)6 is predominantly cleaved into (GlcNAc)2 and (GlcNAc)4, where the (GlcNAc)2 group arises from the nonreducing end of the substrate and is formed as the beta-anomer. With time, transglycosylation occurs, generating (GlcNAc)8 from the product dimer and fresh hexamer. Similar patterns are seen for the cleavage of (GlcNAc)5 and (GlcNAc)4 where dimers cleaved from the nonreducing end reflect the most common binding and hydrolysis pattern. Intrinsic fluorescence measurements suggest the dissociation constant for (GlcNAc)4 is 50 microM. Synthetic substrates with fluorescent leaving groups exhibit complicated profiles in the relationship between initial velocity and substrate concentration, making it difficult to obtain the values of kinetic constants. An improved theoretical analysis of the time-course of (GlcNAc)6 degradation allows the unitary free energy of binding of the individual subsites of the enzyme to be estimated. The free energy values obtained are consistent with the dissociation constant obtained by fluorescence measurements, and generate a model of substrate interaction that can be tested against the crystal structure of the enzyme.
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Affiliation(s)
- T Fukamizo
- Institute of Cellular and Molecular Biology, Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, USA
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