526
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Murashima K, Kosugi A, Doi RH. Synergistic effects on crystalline cellulose degradation between cellulosomal cellulases from Clostridium cellulovorans. J Bacteriol 2002; 184:5088-95. [PMID: 12193625 PMCID: PMC135305 DOI: 10.1128/jb.184.18.5088-5095.2002] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clostridium cellulovorans produces a multienzyme cellulose-degrading complex called the cellulosome. In this study, we determined the synergistic effects on crystalline cellulose degradation by three different recombinant cellulosomes containing either endoglucanase EngE, endoglucanase EngH, or exoglucanase ExgS bound to mini-CbpA, a part of scaffolding protein CbpA. EngE, EngH, and ExgS are classified into the glycosyl hydrolase families 5, 9, and 48, respectively. The assembly of ExgS and EngH with mini-CbpA increased the activity against insoluble cellulose 1.5- to 3-fold, although no effects on activity against soluble cellulose were observed. These results indicated that mini-CbpA could help cellulase components degrade insoluble cellulose but not soluble cellulose. The mixture of the cellulosomes containing ExgS and EngH showed higher activity and synergy degrees than the other cellulosome mixtures, indicating the synergistic effect between EngH and ExgS was the most dominant effect among the three mixtures for crystalline cellulose degradation. Reactions were also performed by adding different cellulosomes in a sequential manner. When ExgS was used for the initial reaction followed by EngE and EngH, almost no synergistic effect was observed. On the other hand, when EngE or EngH was used for the first reaction followed by ExgS, synergistic effects were observed. These results indicated that the initial reactions by EngH and/or EngE promoted cellulose degradation by ExgS.
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527
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Nakashima KI, Watanabe H, Azuma JI. Cellulase genes from the parabasalian symbiont Pseudotrichonympha grassii in the hindgut of the wood-feeding termite Coptotermes formosanus. Cell Mol Life Sci 2002; 59:1554-60. [PMID: 12440775 DOI: 10.1007/s00018-002-8528-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cellulase genes of Pseudotrichonympha grassii (Hypermastigida: Eucomonymphidae), the symbiotic flagellate in the hindgut of the wood-feeding termite Coptotermes formosanus, were isolated and characterized. The nucleotide sequences of the major cellulase component in the hindgut of C. formosanus were determined based on its N-terminal amino acid sequence. The five isolated nucleotide sequences (PgCBH-homos) had an open reading frame of 1350 bp showing similarity to catalytic domains of glycoside hydrolase family (GHF) 7 members, and primary structure comparison with GHF7 members whose tertiary structures are well-characterized revealed the overall similarity between PgCBH-homo and the catalytic domain of a processive cellulase Cel7A (formerly CBHI) from the aerobic fungus Trichoderma reesei. Functional expression of PgCBH-homos in Escherichia coli, using the carboxymethylcellulose-Congo red assay, demonstrated the actual cellulolytic activity of PgCBH-homo. RT-PCR showed that PgCBH-homos were expressed, from the three flagellates in the hindgut, specifically in P. grassii.
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528
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Koivula A, Ruohonen L, Wohlfahrt G, Reinikainen T, Teeri TT, Piens K, Claeyssens M, Weber M, Vasella A, Becker D, Sinnott ML, Zou JY, Kleywegt GJ, Szardenings M, Ståhlberg J, Jones TA. The active site of cellobiohydrolase Cel6A from Trichoderma reesei: the roles of aspartic acids D221 and D175. J Am Chem Soc 2002; 124:10015-24. [PMID: 12188666 DOI: 10.1021/ja012659q] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Trichoderma reesei cellobiohydrolase Cel6A is an inverting glycosidase. Structural studies have established that the tunnel-shaped active site of Cel6A contains two aspartic acids, D221 and D175, that are close to the glycosidic oxygen of the scissile bond and at hydrogen-bonding distance from each other. Here, site-directed mutagenesis, X-ray crystallography, and enzyme kinetic studies have been used to confirm the role of residue D221 as the catalytic acid. D175 is shown to affect protonation of D221 and to contribute to the electrostatic stabilization of the partial positive charge in the transition state. Structural and modeling studies suggest that the single-displacement mechanism of Cel6A may not directly involve a catalytic base. The value of (D2O)(V) of 1.16 +/- 0.14 for hydrolysis of cellotriose suggests that the large direct effect expected for proton transfer from the nucleophilic water through a water chain (Grotthus mechanism) is offset by an inverse effect arising from reversibly breaking the short, tight hydrogen bond between D221 and D175 before catalysis.
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529
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Hatsch D, Phalip V, Jeltsch JM. Development of a bipartite method for Fusarium identification based on cellobiohydrolase-C: CAPS and Western blot analysis. FEMS Microbiol Lett 2002; 213:245-9. [PMID: 12167545 DOI: 10.1111/j.1574-6968.2002.tb11313.x] [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] [Indexed: 11/28/2022] Open
Abstract
The identification of 12 Fusarium strains isolated from diseased hops (Humulus lupulus, L.) was achieved by a strategy based on cellobiohydrolase-C: cleaved amplified polymorphic sequence analysis targeting the gene and the use of an antibody directed against a peptide of the Fusarium graminearum enzyme. This strategy is shown to be rapid and reliable for all the Fusarium of our collection: F. avenaceum, F. graminearum, F. sambucinum, F. sporotrichioides, F. tricinctum and F. venenatum.
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530
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Murashima K, Kosugi A, Doi RH. Thermostabilization of cellulosomal endoglucanase EngB from Clostridium cellulovorans by in vitro DNA recombination with non-cellulosomal endoglucanase EngD. Mol Microbiol 2002; 45:617-26. [PMID: 12139610 DOI: 10.1046/j.1365-2958.2002.03049.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Enhancement of enzyme thermostability by protein engineering gives us information about the thermostabilization mechanism as well as advantages for industrial use of enzymes. In this study, we enhanced the thermostability of endoglucanase EngB, one component of the cellulase complex (cellulosome) from Clostridium cellulovorans, by the directed evolution technique. The library was constructed by in vitro recombination of the genes for EngB and non-cellulosomal cellulase EngD, based on the fact that the catalytic domains of both cellulases were highly homologous. To obtain thermostable clones without loss of activity, the library was screened by a combination of activity and thermostability screening. We obtained three mutants out of 8000 selected clones that showed significantly higher thermostability than those of EngB and EngD without compromising their endoglucanase activities. One of the mutants possessed a sevenfold higher thermostability than EngB. The possible mechanisms of thermostabilization are discussed.
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531
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Xue GP. Characterisation of the DNA-binding profile of barley HvCBF1 using an enzymatic method for rapid, quantitative and high-throughput analysis of the DNA-binding activity. Nucleic Acids Res 2002; 30:e77. [PMID: 12140339 PMCID: PMC137095 DOI: 10.1093/nar/gnf076] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A rapid and quantitative DNA-binding assay was developed based on the translational fusion of a DNA-binding protein (DBP) with a Neocallimastix patriciarum beta-1,4-D-glucanase, CelD. CelD releases a fluorescent 4-methylumbelliferyl product from 4-methylumbelliferyl cellobioside. This hydrolysis activity was used to quantify the amount of DBP-CelD bound to an immobilised biotin-labelled target sequence. The DNA-binding assay can be performed in a 96-well plate format for high- throughput analysis of putative DBPs. This method was applied to analysis of the binding properties and sequence selectivity of a cold-inducible transcription factor HvCBF1 from barley containing an AP2 DNA-binding domain. A base-scanning approach using degenerate oligonucleotide probes was employed for rapid identification of the conserved core motif of the HvCBF1 binding site. Quantitative analysis of the binding site of HvCBF1 using systematic base substitution revealed that a (G/a) (C/t)CGAC sequence was sufficient to constitute a functional motif, where the lower-case letters represent less efficient bases. The method enables us to provide accurate and quantitative data on a comprehensive DNA-binding profile for a cold-inducible AP2 transcription factor as well as information on environmental parameters potentially influencing the DNA-binding activity. The accurate binding sequence data facilitate identification of candidate genes regulated by HvCBF1 from genome sequence databases.
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532
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Kurokawa J, Hemjinda E, Arai T, Kimura T, Sakka K, Ohmiya K. Clostridium thermocellum cellulase CelT, a family 9 endoglucanase without an Ig-like domain or family 3c carbohydrate-binding module. Appl Microbiol Biotechnol 2002; 59:455-61. [PMID: 12172609 DOI: 10.1007/s00253-002-1048-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2002] [Revised: 04/26/2002] [Accepted: 05/10/2002] [Indexed: 11/29/2022]
Abstract
The celT gene of Clostridium thermocellum strain F1 was found downstream of the mannanase gene man26B [Kurokawa J et al. (2001) Biosci Biotechnol Biochem 65:548-554] in pKS305. The open reading frame of celT consists of 1,833 nucleotides encoding a protein of 611 amino acids with a predicted molecular weight of 68,510. The mature form of CelT consists of a family 9 cellulase domain and a dockerin domain responsible for cellulosome assembly, but lacks a family 3c carbohydrate-binding module (CBM) and an immunoglobulin (Ig)-like domain, which are often found with family 9 catalytic domains. CelT devoid of the dockerin domain (CelTDeltadoc) was constructed and purified from a recombinant Escherichia coli, and its enzyme properties were examined. CelTDeltadoc showed strong activity toward carboxymethylcellulose (CMC) and barley beta-glucan, and low activity toward xylan. The V(max) and K(m) values were 137 micro mol min(-1) mg(-1) and 16.7 mg/ml, respectively, for CMC. Immunological analysis indicated that CelT is a catalytic component of the C. thermocellum F1 cellulosome. This is the first report describing the characterization of a family 9 cellulase without an Ig-like domain or family 3c CBM.
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533
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Miettinen-Oinonen A, Suominen P. Enhanced production of Trichoderma reesei endoglucanases and use of the new cellulase preparations in producing the stonewashed effect on denim fabric. Appl Environ Microbiol 2002; 68:3956-64. [PMID: 12147496 PMCID: PMC124001 DOI: 10.1128/aem.68.8.3956-3964.2002] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Trichoderma reesei strains were constructed for production of elevated amounts of endoglucanase II (EGII) with or without cellobiohydrolase I (CBHI). The endoglucanase activity produced by the EGII transformants correlated with the copy number of the egl2 expression cassette. One copy of the egl2 expression cassette in which the egl2 was under the cbh1 promoter increased production of endoglucanase activity 2.3-fold, and two copies increased production about 3-fold above that of the parent strain. When the enzyme with elevated EGII content was used, an improved stonewashing effect on denim fabric was achieved. A T. reesei strain producing high amounts of EGI and -II activities without CBHI and -II was constructed by replacing the cbh2 locus with the coding region of the egl2 gene in the EGI-overproducing CBHI-negative strain. Production of endoglucanase activity by the EG-transformant strain was increased fourfold above that of the host strain. The filter paper-degrading activity of the endoglucanase-overproducing strain was lowered to below detection, presumably because of the lack of cellobiohydrolases.
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534
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Nakashima K, Watanabe H, Saitoh H, Tokuda G, Azuma JI. Dual cellulose-digesting system of the wood-feeding termite, Coptotermes formosanus Shiraki. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2002; 32:777-84. [PMID: 12044494 DOI: 10.1016/s0965-1748(01)00160-6] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The distribution of endo-beta-1,4-glucanase (EG) components in the digestive system of the wood-feeding termite, Coptotermes formosanus Shiraki, was investigated by zymogram analysis using polyacrylamide gel electrophoresis, followed by N-terminal protein sequencing. EG components similar to glycoside hydrolase family (GHF) 9 members were restricted to the salivary glands, the foregut, and the midgut, whereas components similar to GHF7 members were confined to the hindgut where numerous cellulolytic flagellates were harbored. RT-PCR experiments revealed that five GHF9 EG mRNAs (1348 bp) homologous to other termite EGs were expressed in the salivary glands and the midgut. The crude extract prepared from the midgut as well as that from the hindgut produced glucose from crystalline cellulose. These data suggest that C. formosanus has two independent cellulose-digesting systems: one in the midgut where cellulose digestion is accomplished by endogenous cellulases and the other in the hindgut which makes use of other cellulases possibly from symbiotic flagellates.
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535
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Steenbakkers PJM, Ubhayasekera W, Goossen HJAM, van Lierop EMHM, van der Drift C, Vogels GD, Mowbray SL, Op den Camp HJM. An intron-containing glycoside hydrolase family 9 cellulase gene encodes the dominant 90 kDa component of the cellulosome of the anaerobic fungus Piromyces sp. strain E2. Biochem J 2002; 365:193-204. [PMID: 12071852 PMCID: PMC1222669 DOI: 10.1042/bj20011866] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The cellulosome produced by Piromyces sp. strain E2 during growth on filter paper was purified by using an optimized cellulose-affinity method consisting of steps of EDTA washing of the cellulose-bound protein followed by elution with water. Three dominant proteins were identified in the cellulosome preparation, with molecular masses of 55, 80 and 90 kDa. Treatment of cellulose-bound cellulosome with a number of denaturing agents was also tested. Incubation with 0.5% (w/v) SDS or 8 M urea released most cellulosomal proteins, while leaving the greater fraction of the 80, 90 and 170 kDa components. To investigate the major 90 kDa cellulosome protein further, the corresponding gene, cel9A, was isolated, using immunoscreening and N-terminal sequencing. Inspection of the cel9A genomic organization revealed the presence of four introns, allowing the construction of a consensus for introns in anaerobic fungi. The 2800 bp cDNA clone contained an open reading frame of 2334 bp encoding a 757-residue extracellular protein. Cel9A includes a 445-residue glycoside hydrolase family 9 catalytic domain, and so is the first fungal representative of this large family. Both modelling of the catalytic domain as well as the activity measured with low level expression in Escherichia coli indicated that Cel9A is an endoglucanase. The catalytic domain is succeeded by a putative beta-sheet module of 160 amino acids with unknown function, followed by a threonine-rich linker and three fungal docking domains. Homology modelling of the Cel9A dockerins suggested that the cysteine residues present are all involved in disulphide bridges. The results presented here are used to discuss evolution of glycoside hydrolase family 9 enzymes.
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536
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Datsenko KA, Evtushenko AN, Sergeev KV, Dobrynina OI, Bol'shakova TN. [Properties of mutants of bacteria belonging to the genus Erwinia devoid of common components of the phosphoenolpyruvate-dependent phosphotransferase system]. GENETIKA 2002; 38:904-910. [PMID: 12174582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Biochemical consequences of mutational damage to common components of the Erwinia phosphoenolpyruvate-dependent phosphotransferase system (the HPr protein and enzyme I) were studied. The transport of glucose, mannose, fructose, and mannitol in Erwinia was shown to require a preliminary induction of proteins of the phosphotransferase system. A drastic decrease in the rate of the transport of these carbohydrates was observed in ptsI and ptsH mutants. A disturbance in the common components suppresses the synthesis of inducible enzymes (beta-galactosidase, complexes of pectolyases and cellulases) and renders it resistant to catabolite repression by glucose, but mutants were shown to retain intracellular cAMP content. Erwinia mutants devoid of common components of the system lack phytopathogenic features. The appearance of an intact ptsI allele in the cell completely corrected pleiotropic disturbances in these mutants.
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537
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Vinzant TB, Adney WS, Decker SR, Baker JO, Kinter MT, Sherman NE, Fox JW, Himmel ME. Fingerprinting Trichoderma reesei hydrolases in a commercial cellulase preparation. Appl Biochem Biotechnol 2002; 91-93:99-107. [PMID: 11963908 DOI: 10.1385/abab:91-93:1-9:99] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Polysaccharide degrading enzymes from commercial T. reesei broth have been subjected to "fingerprint" analysis by high-resolution 2-D gel electrophoresis. Forty-five spots from 11 x 25 cm Pharmacia gels have been analyzed by LC-MS/MS and the resulting peptide sequences were compared to existing databases. Understanding the roles and relationships of component enzymes from the T. reesei cellulase system acting on complex substrates is key to the development of efficient artificial cellulase systems for the conversion of lignocellulosic biomass to sugars. These studies suggest follow-on work comparing induced and noninduced T. reesei cells at the proteome level, which may elucidate substrate-specific gene regulation and response.
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538
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Mosbah A, Tardif C, Bornet O, Valette O, Henrissat B, Darbon H. Assignment of the 1H, 13C, and 15N resonances of the 22,5 kDa CBM28 module of the cellulase Cel5I of Clostridium cellulolyticum. JOURNAL OF BIOMOLECULAR NMR 2002; 23:157-158. [PMID: 12153043 DOI: 10.1023/a:1016354623398] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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539
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Collén A, Selber K, Hyytiä T, Persson J, Nakari-Setlä T, Bailey M, Fagerström R, Kula MR, Penttilä M, Stålbrand H, Tjerneld F. Primary recovery of a genetically engineered Trichoderma reesei endoglucanase I (Cel 7B) fusion protein in cloud point extraction systems. Biotechnol Bioeng 2002; 78:385-94. [PMID: 11948445 DOI: 10.1002/bit.10232] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Here we present data to demonstrate how partitioning of a hydrophilic enzyme can be directed to the hydrophobic detergent-enriched phase of an aqueous two-phase system by addition of short stretches of amino acid residues to the protein molecule. The target enzyme was the industrially important endoglucanase I, EGI (endo-1,4-beta-D-glucan-4-glucanohydrolase, EC 3.2.1.4, Cel7B) of Trichoderma reesei. We investigated the partitioning of three EGI variants containing various C-terminal peptide extensions including Trp-Pro motifs of different lengths and localizations. Additionally, a recently developed system composed of the thermoseparating copolymer HM-EOPO was utilized to study the effects of fusion tags. The addition of peptides containing tryptohan residues enhanced the partitioning of EGI to the HM-EOPO-rich phase. The system composed of a nonionic detergent (Agrimul NRE1205) resulted in the highest partition coefficient (K = 31) and yield (90%) with the construct EGI(core-P5)(WP)(4) containing (Trp-Pro)(4) after a short linker stretch. A recombinant strain of T. reesei Rut-C30 for large-scale production was constructed in which the fusion protein EGI(core-P5)(WP)(4) was expressed from the strong promoter of the cellulase gene cbh1. The fusion protein was successfully expressed and secreted from the fungus during shake-flask cultivations. Cultivation in a 28-L bioreactor however, revealed that the fusion protein is sensitive to proteases. Consequently, only low production levels were obtained in large-scale production trials.
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540
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Németh A, Kamondi S, Szilágyi A, Magyar C, Kovári Z, Závodszky P. Increasing the thermal stability of cellulase C using rules learned from thermophilic proteins: a pilot study. Biophys Chem 2002; 96:229-41. [PMID: 12034443 DOI: 10.1016/s0301-4622(02)00027-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Some structural features underlying the increased thermostability of enzymes from thermophilic organisms relative to their homologues from mesophiles are known from earlier studies. We used cellulase C from Clostridium thermocellum to test whether thermostability can be increased by mutations designed using rules learned from thermophilic proteins. Cellulase C has a TIM barrel fold with an additional helical subdomain. We designed and produced a number of mutants with the aim to increase its thermostability. Five mutants were designed to create new electrostatic interactions. They all retained catalytic activity but exhibited decreased thermostability relative to the wild-type enzyme. Here, the stabilizing contributions are obviously smaller than the destabilization caused by the introduction of the new side chains. In another mutant, the small helical subdomain was deleted. This mutant lost activity but its melting point was only 3 degrees C lower than that of the wild-type enzyme, which suggests that the subdomain is an independent folding unit and is important for catalytic function. A double mutant was designed to introduce a new disulfide bridge into the enzyme. This mutant is active and has an increased stability (deltaT(m)=3 degrees C, delta(deltaG(u))=1.73 kcal/mol) relative to the wild-type enzyme. Reduction of the disulfide bridge results in destabilization and an altered thermal denaturation behavior. We conclude that rules learned from thermophilic proteins cannot be used in a straightforward way to increase the thermostability of a protein. Creating a crosslink such as a disulfide bond is a relatively sure-fire method but the stabilization may be smaller than calculated due to coupled destabilizing effects.
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541
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Linder M, Winiecka-Krusnell J, Linder E. Use of recombinant cellulose-binding domains of Trichoderma reesei cellulase as a selective immunocytochemical marker for cellulose in protozoa. Appl Environ Microbiol 2002; 68:2503-8. [PMID: 11976127 PMCID: PMC127560 DOI: 10.1128/aem.68.5.2503-2508.2002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2001] [Accepted: 11/29/2001] [Indexed: 11/20/2022] Open
Abstract
Some unicellular organisms are able to encyst as a protective response to a harmful environment. The cyst wall usually contains chitin as its main structural constituent, but in some cases, as in Acanthamoeba, it consists of cellulose instead. Specific cytochemical differentiation between cellulose and chitin by microscopy has not been possible, due to the similarity of their constituent beta-1,4-linked hexose backbones. Thus, various fluorescent brightening agents and lectins bind to both cellulose and chitin. We have used a recombinant cellulose-binding protein consisting of two cellulose-binding domains (CBDs) from Trichoderma reesei cellulases linked together in combination with monoclonal anticellulase antibodies and anti-mouse immunoglobulin fluorescein conjugate to specifically stain cellulose in the cysts of Acanthamoeba strains for fluorescence microscopy imaging. Staining was observed in ruptured cysts and frozen sections of cysts but not in intact mature cysts. No staining reaction was observed with the chitin-containing cyst walls of Giardia intestinalis, Entamoeba dispar, or Pneumocystis carinii. Thus, the recombinant CBD can be used as a marker to distinguish between cellulose and chitin. Thirteen of 25 environmental or clinical isolates of amoebae reacted in the CBD binding assay. All 13 isolates were identified as Acanthamoeba spp. Five isolates of Hartmannella and seven isolates of Naegleria tested negative in the CBD binding assay. Whether cyst wall cellulose really is a unique property of Acanthamoeba spp. among free-living amoebae, as suggested by our findings, remains to be shown in more extensive studies.
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542
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Goedegebuur F, Fowler T, Phillips J, van der Kley P, van Solingen P, Dankmeyer L, Power SD. Cloning and relational analysis of 15 novel fungal endoglucanases from family 12 glycosyl hydrolase. Curr Genet 2002; 41:89-98. [PMID: 12073090 DOI: 10.1007/s00294-002-0290-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2001] [Accepted: 03/06/2002] [Indexed: 11/25/2022]
Abstract
Cellulases belong to the large family of glycosyl hydrolases (GHs) and are produced by a variety of bacteria and fungi. These extracellular enzymes act as endoglucanases (EGs), cellobiohydrolases or beta-glucosidases. In this paper, we describe molecular screening for EGs from the GH family 12. Using three homologous sequence boxes deduced from five previously known members of the family, we analysed 22 cellulase-producing fungal strains obtained from a diverse area of the fungal kingdom. Polymerase chain reactions using degenerate primers designed to the homologous protein boxes were used to identify the family 12 homologues. Several fungi showed the presence of multiple versions of the gene, while amino acid sequence analysis showed diversity in 15 novel members of the family, ranging from 26% to 96% similarity. Our sequence analysis shows that the phylogenetic tree of family 12 EGs can be divided into four subfamilies: 12-1 (fungal group I), 12-2 (fungal group II), 12-3 ( Streptomyces group in which Rhodothermus marinus fits) and 12-4 ( Thermophiles group). Erwinia carotovora may form a new subgroup.
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543
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Hakamada Y, Endo K, Takizawa S, Kobayashi T, Shirai T, Yamane T, Ito S. Enzymatic properties, crystallization, and deduced amino acid sequence of an alkaline endoglucanase from Bacillus circulans. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1570:174-80. [PMID: 12020807 DOI: 10.1016/s0304-4165(02)00194-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A high-isoelectric-point (pI), alkaline endo-1,4-beta-glucanase (Egl-257) of Bacillus circulans KSM-N257 was purified to homogeneity and crystallized. The purified enzyme hydrolyzed carboxymethyl cellulose (CMC) with optima of pH 8.5 and 55 degrees C. The molecular mass was 43 kDa, and the pI was pH 9.3. The structural gene contained a single open reading frame of 1221 bp, corresponding to 407 amino acids (aa), including a 30-aa signal peptide (377 aa and 41,680 Da for the mature enzyme). Egl-257 hydrolyzed lichenan and showed 76.3% aa identity to a lichenase from B. circulans WL-12 belonging to glycosyl hydrolase family 8 but did not hydrolyze laminarin, curdran, and xylan at all. This indicates that Egl-257 is a true endo-1,4-beta-glucanase. However, this enzyme was not active on p-nitrophenyl beta-D-cellotrioside and p-nitrophenyl beta-D-cellotetraoside. It was crystallized by the hanging-drop vapor-diffusion method with phosphate plus CdCl(2) as precipitant. Pyramid-like crystals were formed, and they diffracted X-rays beyond 2.2 A resolution. It belongs to the space group P2(1)2(1)2(1) with unit cell parameters of a=62.5 A, b=71.7 A, and c=88.6 A.
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544
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Hasper AA, Dekkers E, van Mil M, van de Vondervoort PJI, de Graaff LH. EglC, a new endoglucanase from Aspergillus niger with major activity towards xyloglucan. Appl Environ Microbiol 2002; 68:1556-60. [PMID: 11916668 PMCID: PMC123852 DOI: 10.1128/aem.68.4.1556-1560.2002] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel gene, eglC, encoding an endoglucanase, was cloned from Aspergillus niger. Transcription of eglC is regulated by XlnR, a transcriptional activator that controls the degradation of polysaccharides in plant cell walls. EglC is an 858-amino-acid protein and contains a conserved C-terminal cellulose-binding domain. EglC can be classified in glycoside hydrolase family 74. No homology to any of the endoglucanases from Trichoderma reesei was found. In the plant cell wall xyloglucan is closely linked to cellulose fibrils. We hypothesize that the EglC cellulose-binding domain anchors the enzyme to the cellulose chains while it is cleaving the xyloglucan backbone. By this action it may contribute to the degradation of the plant cell wall structure together with other enzymes, including hemicellulases and cellulases. EglC is most active towards xyloglucan and therefore is functionally different from the other two endoglucanases from A. niger, EglA and EglB, which exhibit the greatest activity towards beta-glucan. Although the mode of action of EglC is not known, this enzyme represents a new enzyme function involved in plant cell wall polysaccharide degradation by A. niger.
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545
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Belaich A, Parsiegla G, Gal L, Villard C, Haser R, Belaich JP. Cel9M, a new family 9 cellulase of the Clostridium cellulolyticum cellulosome. J Bacteriol 2002; 184:1378-84. [PMID: 11844767 PMCID: PMC134834 DOI: 10.1128/jb.184.5.1378-1384.2002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A new cellulosomal protein from Clostridium cellulolyticum Cel9M was characterized. The protein contains a catalytic domain belonging to family 9 and a dockerin domain. Cel9M is active on carboxymethyl cellulose, and the hydrolysis of this substrate is accompanied by a decrease in viscosity. Cel9M has a slight, albeit significant, activity on both Avicel and bacterial microcrystalline cellulose, and the main soluble sugar released is cellotetraose. Saccharification of bacterial microcrystalline cellulose by Cel9M in association with two other family 9 enzymes from C. cellulolyticum, namely, Cel9E and Cel9G, was measured, and it was found that Cel9M acts synergistically with Cel9E. Complexation of Cel9M with the mini-CipC1 containing the cellulose binding domain, the X2 domain, and the first cohesin domain of the scaffoldin CipC of the bacterium did not significantly increase the hydrolysis of Avicel and bacterial microcrystalline cellulose.
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546
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Cho SJ, Par SR, Kim MK, Lim WJ, Ryu SK, An CL, Hong SY, Kim H, Cho YU, Yun HD. Cloning of the cel8Y gene from Pectobacterium chrysanthemi PY35 and its comparison to cel genes of soft-rot Pectobacterium. Mol Cells 2002; 13:28-34. [PMID: 11911471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
The phytopathogenic Pectobacterium chrysanthemi (Pch) PY35 secretes multiple isozymes of plant cell wall degrading enzyme cellulases. We cloned a second cel gene that encodes cellulase in Pch PY35. The inserted 2 kb fragment was subcloned in order to geneate pPY710 (cel8Y). The structural organization of the cel8Y gene consists of an open reading frame (ORF) of 999 bp that encodes 332 amino acid residues with a signal peptide of 23 amino acids. The predicted amino acid sequence of Cel8Y was very similar to that of Cellulomonas uda, but completely different from that of the Cel5Z of Pch PY35. It belonged to the glycoside hydrolase family 8, based on amino acid sequence similarities in contrast to Cel5Z of Pch PY35, which was confirmed as family 5. Cel8Y was not closely related to the known cellulases of Pectobacterium. It had the conserved region of the glycoside hydrolase family 8, ASDGDVLIAWALLKAGNKW. The apparent molecular mass of the Cel8Y protein was calculated to be approximately 34 kDa by a carboxymethylcellulosesodium dodecyl sulfate-polyacrylamide gel electrophoresis (CMC-SDS-PAGE). The Cel8Y had a calculated pl of 6.49. It was optimally active at pH 7 with an approximate optimal temperature around 40 degrees C. The cellulase activity of Cel8Y was lower than that of Cel5Z.
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547
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Park SR, Cho SJ, Kim MK, Ryu SK, Lim WJ, An CL, Hong SY, Kim JH, Kim H, Yun HD. Activity enhancement of Cel5Z from Pectobacterium chrysanthemi PY35 by removing C-terminal region. Biochem Biophys Res Commun 2002; 291:425-30. [PMID: 11846423 DOI: 10.1006/bbrc.2002.6437] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The phytopathogenic bacterium Pectobacteium chrysanthemi PY35 secretes Cel5Z endoglucanase belonging to the glycoside hydrolase family 5 of EC 3.2.1.4. The mutation of cel5Z::Omega gene was constructed by cloning the 2.0-kb SmaI fragment containing the streptomycin/spectinomycin-resistance gene of pHP45(Omega) into the BalI site of pPY100. The insertion of Omega fragment generated a new stop codon, removing the Ser/Thr-rich linker region and the cellulose binding domain (CBD) in the C-terminal region of cel5Z gene. By subsequent subcloning from this 4.9-kb fragment (pPY1001), a 1.0-kb (pPY1002) fragment was obtained and designated as cel5Z::Omega. The cel5Z::Omega gene had an open reading frame (ORF) of 1011 bp, encoding 336 amino acids, starting with an ATG codon and ending with a new TGA stop codon. The molecular mass of the Cel5Z::Omega protein in E. coli transformant appeared to be 32 kDa by SDS-PAGE analysis in the presence of carboxymethyl-cellulose (CMC). The Cel5Z::Omega protein hydrolyzed CMC with 1.7-fold higher activity than the intact Cel5Z cellulase.
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548
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Schaeffer F, Matuschek M, Guglielmi G, Miras I, Alzari PM, Béguin P. Duplicated dockerin subdomains of Clostridium thermocellum endoglucanase CelD bind to a cohesin domain of the scaffolding protein CipA with distinct thermodynamic parameters and a negative cooperativity. Biochemistry 2002; 41:2106-14. [PMID: 11841200 DOI: 10.1021/bi011853m] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mutagenized dockerin domains of endoglucanase CelD (type I) and of the cellulosome-integrating protein CipA (type II) were constructed by swapping residues 10 and 11 of the first or the second duplicated segment between the two polypeptides. These residues have been proposed to determine the specificity of cohesin-dockerin interactions. The dockerin domain of CelD still bound to the seventh cohesin domain of CipA (CohCip7), provided that mutagenesis occurred in one segment only. Binding was no longer detected by nondenaturing gel electrophoresis when both segments were mutagenized. The dockerin domain of CipA bound to the cohesin domain of SdbA as long as the second segment was intact. None of the mutated dockerins displayed detectable binding to the noncognate cohesin domain. Isothermal titration calorimetry showed that binding of the CelD dockerin to CohCip7 occurred with a high affinity [K(a) = (2.6 +/- 0.5) x 10(9) M(-1)] and a 1:1 stoichiometry. The reaction was weakly exothermic (DeltaHdegrees = -2.22 +/- 0.2 kcal x mol(-1)) and largely entropy driven (TDeltaSdegrees = 10.70 +/- 0.5 kcal x mol(-1)). The heat capacity change on complexation was negative (DeltaC(p) = -305 +/- 15 cal x mol(-1) x K(-1)). These values show that cohesin-dockerin binding is mainly hydrophobic. Mutations in the first or the second dockerin segment reduced or enhanced, respectively, the hydrophobic character of the interaction. Due to partial enthalpy-entropy compensation, these mutations induced only small changes in binding affinity. However, the binding affinity was strongly decreased when both segments were mutated, indicating strong negative cooperativity between the two mutated sites.
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549
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Song SB, Kim KK, Kim KE. T vectors with endoglucanase A (celA) gene for direct detection of PCR clones. Biotechniques 2002; 32:248, 250, 252. [PMID: 11848396 DOI: 10.2144/02322bm03] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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550
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Kosugi A, Murashima K, Tamaru Y, Doi RH. Cell-surface-anchoring role of N-terminal surface layer homology domains of Clostridium cellulovorans EngE. J Bacteriol 2002; 184:884-8. [PMID: 11807046 PMCID: PMC134812 DOI: 10.1128/jb.184.4.884-888.2002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
engE, coding for endoglucanase E, one of the three major subunits of the Clostridium cellulovorans cellulosome, has been cloned and sequenced (Y. Tamaru and R. H. Doi, J. Bacteriol. 181:3270-3276, 1999). The N-terminal-half region of EngE possesses three repeated surface layer homology (SLH) domains, which are homologous to those of some bacterial S-layer proteins. Also, the C-terminal-half region consists of a catalytic domain of glycosyl hydrolase family 5 and a duplicated sequence (dockerin) for binding EngE to scaffolding protein CbpA. Our hypothesis is that the SLH domains serve in the role of anchoring to the cell surface. This model was investigated by using recombinant EngEs (rEngE) with and without SLH domains that were synthesized in Escherichia coli and cell wall preparations from C. cellulovorans. When rEngE and SLH polypeptides of EngE were incubated with cell wall fragments prepared by sodium dodecyl sulfate treatment, these proteins bound strongly to the cell wall. However, rEngEs without SLH domains lost their ability to bind to cell walls. When rEngE was incubated with mini-CbpA, consisting of two cohesin domains, and cell wall fragments, the mini-CbpA was able to bind to the cell wall with rEngE. However, the binding of mini-CbpA was dramatically inhibited by addition of a chelating reagent, such as EDTA, which prevents cohesin-dockerin interactions. These results suggest not only that the SLH domains of EngE can bind to the cell surface but also that EngE plays an anchoring role for cellulosomes through the interaction of its dockerin domain with a CbpA cohesin.
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