The structure of endoglucanase I (Trichoderma resei) in solution

Author(s):  
P. P. Abuja ◽  
M. Hayn ◽  
H. Chen ◽  
H. Esterbauer
Keyword(s):  
1998 ◽  
Vol 335 (2) ◽  
pp. 409-416 ◽  
Author(s):  
Lloyd F. MACKENZIE ◽  
Gerlind SULZENBACHER ◽  
Christina DIVNE ◽  
T. Alwyn JONES ◽  
Helle F. WÖLDIKE ◽  
...  

Cellulose is the major polysaccharide component of the plant cell wall and the most abundant naturally produced macromolecule on Earth. The enzymic degradation of cellulose, by cellulases, is therefore of great environmental and commercial significance. Cellulases are found in 12 of the glycoside hydrolase families classified according to their amino acid sequence similarities. Endoglucanase I (Cel7B), from the soft-rot fungus Humicola insolens, is a family 7 enzyme. The structure of the native form of Cel7B from H. insolens at 2.2 Å resolution has been solved by molecular replacement using the known Trichoderma reesei cellobiohydrolase I [Divne, Ståhlberg, Reinikainen, Ruohonen, Pettersson, Knowles, Teeri and Jones (1994) Science265, 524–528] structure as the search model. Cel7B catalyses hydrolysis of the β-1,4 glycosidic linkages in cellulose with net retention of anomeric configuration. The catalytic nucleophile at the active site of Cel7B has been identified as Glu-197 by trapping of a 2-deoxy-2-fluorocellotriosyl enzyme intermediate and identification of the labelled peptide in peptic digests by tandem MS. Site-directed mutagenesis of both Glu-197 and the prospective catalytic acid, Glu-202, results in inactive enzyme, confirming the critical role of these groups for catalysis.


2002 ◽  
Vol 1569 (1-3) ◽  
pp. 139-150 ◽  
Author(s):  
Anna Collén ◽  
Josefine Persson ◽  
Markus Linder ◽  
Tiina Nakari-Setälä ◽  
Merja Penttilä ◽  
...  

Gene ◽  
1986 ◽  
Vol 45 (3) ◽  
pp. 253-263 ◽  
Author(s):  
Merja Penttilä ◽  
Päivi Lehtovaara ◽  
Helena Nevalainen ◽  
Ramagauri Bhikhabhai ◽  
Jonathan Knowles

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 130 ◽  
Author(s):  
Aslı Yenenler ◽  
Hasan Kurt ◽  
Osman Sezerman

Utilizing plant-based materials as a biofuel source is an increasingly popular attempt to redesign the global energy cycle. This endeavour underlines the potential of cellulase enzymes for green energy production and requires the structural and functional engineering of natural enzymes to enhance their utilization. In this work, we aimed to engineer enzymatic and functional properties of Endoglucanase I (EGI) by swapping the Ala43-Gly83 region of Cellobiohydrolase I (CBHI) from Trichoderma reesei. Herein, we report the enhanced enzymatic activity and improved thermal stability of the engineered enzyme, called EGI_swapped, compared to EGI. The difference in the enzymatic activity profile of EGI_swapped and the EGI enzymes became more pronounced upon increasing metal-ion concentrations in the reaction media. Notably, the engineered enzyme retained a considerable level of enzymatic activity after thermal incubation for 90 min at 70 °C while EGI completely lost its enzymatic activity. Circular Dichroism spectroscopy studies revealed distinctive conformational and thermal susceptibility differences between EGI_swapped and EGI enzymes, confirming the improved structural integrity of the swapped enzyme. This study highlights the importance of swapping the metal-ion coordination region in the engineering of EGI enzyme for enhanced structural and thermal stability.


1990 ◽  
Vol 270 (1) ◽  
pp. 251-256 ◽  
Author(s):  
M Claeyssens ◽  
H van Tilbeurgh ◽  
J P Kamerling ◽  
J Berg ◽  
M Vrsanska ◽  
...  

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 (kcat., 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-O-beta-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 D-glucose 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 beta 1-4 configuration of the newly formed bond was proved.


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