A new appraisal of the endoglucanases of the fungus <i>Trichoderma reesei</i>

Niku‐Paavola, Marja‐Leena; Lappalainen, Arja; Enari, Tor-Magnus; Nummi, Martti

doi:10.1042/bj2310075

Cited by 49 publications

(17 citation statements)

References 24 publications

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“…A similar bacterial endoglucanase with 97% homology has been reported; however, limited characterization of this enzyme has been performed (28). Endoglucanase has been reported in several fungal species, and we found the specific activity of Endo5A to be similar (25,26). Xyl11D of Paenibacillus ICGEB2008 had a relatively low molecular mass (ϳ20 kDa) and contained a catalytic domain belonging to glycosyl hydrolase family 11.…”

Section: Discussionmentioning

confidence: 49%

Synthesis and Characterization of Chimeric Proteins Based on Cellulase and Xylanase from an Insect Gut Bacterium

Adlakha

Rajagopal

Kumar

et al. 2011

Appl Environ Microbiol

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Insects living on wood and plants harbor a large variety of bacterial flora in their guts for degrading biomass. We isolated a Paenibacillus strain, designated ICGEB2008, from the gut of a cotton bollworm on the basis of its ability to secrete a variety of plant-hydrolyzing enzymes. In this study, we cloned, expressed, and characterized two enzymes, ␤-1,4-endoglucanase (Endo5A) and ␤-1,4-endoxylanase (Xyl11D), from the ICGEB2008 strain and synthesized recombinant bifunctional enzymes based on Endo5A and Xyl11D. The gene encoding Endo5A was obtained from the genome of the ICGEB2008 strain by shotgun cloning. The gene encoding Xyl11D was obtained using primers for conserved xylanase sequences, which were identified by aligning xylanase sequences in other species of Paenibacillus. Endo5A and Xyl11D were overexpressed in Escherichia coli, and their optimal activities were characterized. Both Endo5A and Xyl11D exhibited maximum specific activity at 50°C and pH 6 to 7. To take advantage of this feature, we constructed four bifunctional chimeric models of Endo5A and Xyl11D by fusing the encoding genes either end to end or through a glycine-serine (GS) linker. We predicted three-dimensional structures of the four models using the I-TASSER server and analyzed their secondary structures using circular dichroism (CD) spectroscopy. The chimeric model Endo5A-GS-Xyl11D, in which a linker separated the two enzymes, yielded the highest C-score on the I-TASSER server, exhibited secondary structure properties closest to the native enzymes, and demonstrated 1.6-fold and 2.3-fold higher enzyme activity than Endo5A and Xyl11D, respectively. This bifunctional enzyme could be effective for hydrolyzing plant biomass owing to its broad substrate range.Cellulose and hemicellulose constitute ϳ70 to 80% of wood and agricultural biomass and can serve as an abundant and inexpensive source of fermentable sugar for producing various chemicals and biofuels (34,35). Three enzymes hydrolyze the ␤-1,4 glycosidic linkages that are present in cellulose. ␤-1,4-Endoglucanases cleave within the chain, cellobiohydrolases cleave at either end of the chain, and ␤-glucosidases break oligomers into monomers (22). Another class of enzymes, which includes xylanase and xylosidase, hydrolyzes ␤-1,4-xylan into xylose and is involved in the breakdown of hemicellulose (2).Although a process to convert lignocellulosic biomass into ethanol has been developed by various research groups, costeffective production of lignocellulosic ethanol is still a major issue, largely because of the high cost associated with the enzymes (20,22,34). Fungi such as Trichoderma reesei and Aspergillus niger are common sources of plant-hydrolyzing enzymes (6, 23, 32); however, these enzymes require acidic pH (30) and have a short half-life at high temperatures (12) and a low specific activity (10), which are bottlenecks to using fungal enzymes. Bacterial plant-hydrolyzing enzymes have been reported to work at a wide range of pHs and temperatures (10, 21) and, therefore, are potential cata...

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Section: Discussionmentioning

confidence: 49%

Synthesis and Characterization of Chimeric Proteins Based on Cellulase and Xylanase from an Insect Gut Bacterium

Adlakha

Rajagopal

Kumar

et al. 2011

Appl Environ Microbiol

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“…Although endoglucanase I (58 kDa) has been well documented in the literature, the other endoglucanases detected here are less easy to compare. A 67-kDa endoglucanase has been described previously (24,32), whereas several endoglucanases exhibiting molecular masses around 50 kDa have been reported (2,8,10,29); however, the relationship of these proteins to each other cannot be deduced, since controversial properties (specificity, isoelectric points) have been reported. The 25-kDa endoglucanase detected here, on the other hand, appears to be identical to the low-molecularweight endoglucanase reported before (9).…”

Section: Methodsmentioning

confidence: 99%

“…With respect to the endoglucanase components from T. reesei, the existence of two different endoglucanases (I and III) differing in structure and specificity (3,4,10,16,24,27,30), which additionally occur in multiple forms (4,11,12,17,21), has been established. In the present paper we report a reexamination of the control of formation of individual * Corresponding author.…”

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confidence: 99%

Differential regulation of synthesis of multiple forms of specific endoglucanases by Trichoderma reesei QM9414

1988

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A method consisting of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subsequent detection of endoglucanases by blotting with a polyclonal antibody against endoglucanase I was used to investigate the effect of induction and carbon catabolite derepression on the synthesis of multiple forms of endoglucanase I by Trichoderma reesei. Five forms appeared upon growth on cellulose, whereas four and only two appeared upon growth on lactose (carbon catabolite derepression) and induction by sophorose in a resting cell system, respectively. All endoglucanases detected resembled endoglucanase I in their specificity, since they exhibited no activity toward xylan or paranitrophenyl-,-D-lactobioside. A small (25-kiodalton) endoglucanase only appeared during growth on cellulose. None of the multiple forms arose by postsecretional modification. The results indicate that sophorose may not be the only compound mediating cellulose induction of the specific endoglucanases in T. reesei.

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“…carboxymethylcellulose), are, however, completely different. The cellobiohydrolase I attacks very slowly and is adsorbed very strongly to (semi-)crystalline cellulose (Avicel), whereas endoglucanase I has been shown to act primarily on soluble cellulose derivatives and xylans (Niku-Paavola et al, 1985). Both enzymes catalyse the hydrolysis of the lower members of the cellodextrin series .…”

Section: Introductionmentioning

confidence: 99%

Studies of the cellulolytic system of the filamentous fungus Trichoderma reesei QM 9414. Substrate specificity and transfer activity of endoglucanase I

Claeyssens

Tilbeurgh

Kamerling

et al. 1990

Biochemical Journal

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The Netherlands, and $Chemicky ustav Slovenskej akademie vied, Dubravska cesta, 9, CS-8423 Bratislava, Czechoslovakia Endoglucanase I from the filamentous fungus Trichoderma reesei catalyses hydrolysis and glycosyl-transfer reactions of cello-oligosaccharides. Initial bond-cleaving frequencies determined with 1-3H-labelled cello-oligosaccharides proved to be substrate-concentration-dependent. Using chromophoric glycosides and analysing the reaction products by h.p.l.c., kinetic data are obtained and, as typical for an endo-type depolymerase, apparent hydrolytic parameters (kct., kcat /Km) increase steadily as a function of the number of glucose residues. At high substrate concentrations, and for both free cellodextrins and their aromatic glycosides, complex patterns (transfer reactions) are, however, evident. In contrast with the corresponding lactosides and 1-thiocellobiosides, and in conflict with the expected specificity, aromatic 1-0-,6-cellobiosides are apparently hydrolysed at both scissile bonds, yielding the glucoside as one of the main reaction products. Its formation rate is clearly non-hyperbolically related to the substrate concentration and, since the rate of Dglucose formation is substantially lower, strong indications for dismutation reactions (self-transfer) are again obtained. Evidence for transfer reactions catalysed by endoglucanase I further results from experiments using different acceptor and donor substrates. A main transfer product accumulating in a digest containing a chromophoric 1-thioxyloside was isolated and its structure elucidated by proton n.m.r. spectrometry (500 MHz). The fll-4 configuration of the newly formed bond was proved. INTRODUCTIONThe filamentous fungus Trichoderma reesei secretes a very efficient cellulolytic system which contains several components.

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A new appraisal of the endoglucanases of the fungus Trichoderma reesei

Cited by 49 publications

References 24 publications

Synthesis and Characterization of Chimeric Proteins Based on Cellulase and Xylanase from an Insect Gut Bacterium

Synthesis and Characterization of Chimeric Proteins Based on Cellulase and Xylanase from an Insect Gut Bacterium

Differential regulation of synthesis of multiple forms of specific endoglucanases by Trichoderma reesei QM9414

Studies of the cellulolytic system of the filamentous fungus Trichoderma reesei QM 9414. Substrate specificity and transfer activity of endoglucanase I

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