Latest Research on Endoglucanase : Dec 2021

Structure and function of endoglucanase V

CELLULOSE is the major polysaccharide component of plant cell walls and is the most abundant organic compound on the planet. A number of bacterial1 and fungal2 organisms can use cellulose as a food source, possessing cellulases (cellobiohydrolases and endoglucanases) that can catalyse the hydrolysis of the β-(1,4) glycosidic bonds. They can be classified into seven distinct families3. The three-dimensional structures of members of two of these families are known4,5. Here we report the structure of a third cellulase, endoglucanase V, whose sequence is not represented in any of the above families. The enzyme is structurally distinct from the previously determined cellulases but is similar to a recently characterized plant defence protein6. The active site region resembles that of lysozyme, despite the lack of structural similarity between these two enzymes.[1]


EGIII, a new endoglucanase from Trichoderma reesei: the characterization of both gene and enzyme

A novel endoglucanase from Trichoderma reesei, EGIII, has been purified and its catalytic properties have been studied. The gene for that enzyme (egl3) and cDNA have been cloned and sequenced. The deduced EGIII protein shows clear sequence homology to a Schizophyllum commune enzyme (M. Yaguchi, personal communication), but is very different from the three other T. reesei cellulases with known structure. Nevertheless, all the four T. reesei cellulases share two common, adjacent sequence domains, which apparently can be removed by proteolysis. These homologous sequences reside at the N termini of EGIII and the cellobiohydrolase CBHII, but at the C termini of EGI and CBHI. Comparison of the fungal cellulase structures has led to re-evaluation of hypotheses concerning the localization of the active sites.[2]


Solid state fermentation of agricultural wastes for endoglucanase production

The lignocellulosic biomass (especially agricultural wastes) is known to be an excellent carbon source for microbial enzyme production. In this paper, the cellulase production from lignocellulosic materials under solid state fermentation (SSF) was investigated. The effects of fermentation conditions, such as moisture content, initial pH, temperature, and composition of mixed substrate (wheat straw and wheat bran) on endoglucanase production by Aspergillus niger 38 were studied. With a moisture content of 74% a pH range of 4.5–5.5 on mixed substrate containing wheat straw:wheat bran of 9:1, 14.80 international units (UI) endoglucanase activity/ml were obtained in 96 h. [3]


Increase in Endoglucanase Productivity and Mycelial Stability of Rhizopus oryzae by Classical Mutagenesis

Aim: To develop a mutant strain with high endoglucanase productivity and optimization of some cultivation parameters.

Place and Duration of Study: Microbiology Research Laboratory, Department of Zoology, Molecular Biology & Genetics, Presidency University, College Street, Kolkata: 700 073, India, between Aug, 2010 and March 2011.

Methodology: The wild strain of Rhizopus oryzae PR7 MTCC 9642 was subjected to classical mutagenesis by suspending 5 hyphal discs (0.5 cm) in 10ml of N-methyl-N’-nitro-N-nitrosoguanidine (MNNG) solutions of various concentrations (125-1000µg). The in situ cellulolytic activity of the colonies of the mutant strains on the plates were measured by using alcoholic iodine solution and the highest enzyme producing mutant was selected. The mutant strain was later cultivated in presence of various domestic wastes at various pH, temperature, time. The morphological alteration was also checked by staining with fluorescent dye.

Results: Out of 50 mutants, strain A7 was selected that showed about 33% increase in endoglucanase synthesis utilizing orange bagasse as sole carbon source in a shake flask screen. The strain was found to have the same pH and temperature optima, but could achieve highest level of enzyme production earlier than that by its wild counterpart. Being a dimorphic fungus, the wild type strain of Rhizopus oryzae, showed a transformation to yeast like pelleted form, whereas the mutant strain A 7 showed persistent filamentous structure indicating the achievement of a structural stability in presence of environmental stress.

Conclusion: The present mutant strain could ferment orange bagasse and showed an increased production of endoglucanase with minimized time consumption with greater mycelial stability against various environmental stresses. These achievements will definitely add economy in industrial production of endoglucanse at a nominal cost. [4]


Potential of Azadirachtin and Neem (Azadirachta indica) Based Saponins as Biopesticides for In vitro Insect Pests Cellulase (Beta-1,4-Endoglucanase) Enzyme Inhibition and In vivo Repellency on Tribolium castaneum

Aims: The work was undertaken to identify the role of Neem derived compounds (saponins and azadirachtin) on the digestive cellulose hydrolyzing enzyme activity of red flour beetle   (T. castaneum), rice grasshopper (Oxya chinensis) and red pumpkin beetle (Aulacophora foveicolis).

Place and Duration of Study: The work was carried out at the Institute of Biochemistry and Biotechnology University of the Punjab Lahore Pakistan.

Methodology: Total cellular proteins were isolated from the insect’s gut and salivary glands and were tested for cellulose hydrolyzing activity on substrate agar plates. Saponins and Azadirachtin were isolated from Azadirachta indica tissues and used for enzyme inhibition studies. Repellancy test was performed for T. Castaneum, using saponins and Azadirachtin. For computational studies sequence of endoglucanase gene was identified from T. castaneum genome and protein structure was deduced.

Results: Saponins were able to inhibit beta-1,4-endoglucanase  enzyme activity, present in all the three insect pests. A computational dissection of T. castaneum endoglucanase enzyme, deduced from T. castaneum genome, showed that there were five cys involved in the formation of disulphide bridges in the molecule. The disulfide bridges did not provide any protection to endoglucanase active site. Azadirachtin had no effect on cellulase activity of Oxya chinensis and Aulacophora foveicolis, while beta-1,4-endoglucanase activity of T. castaneum was inhibited. Repellency test for T. castaneum revealed that each group of compounds (Saponins and Azadirachtin) was able to repel the insect. Conclusion: Neem derived compounds had a considerable inhibitory effect on the digestive cellulose hydrolyzing enzyme of T. castaneum. [5]


Reference

[1] Davies, G.J., Dodson, G.G., Hubbard, R.E., Tolley, S.P., Dauter, Z., Wilson, K.S., Hjort, C., Mikkelsen, J.M., Rasmussen, G. and Schülein, M., 1993. Structure and function of endoglucanase V. Nature, 365(6444), pp.362-364.

[2] Saloheimo, M., Lehtovaara, P., Penttilä, M., Teeri, T.T., Ståhlberg, J., Johansson, G., Pettersson, G., Claeyssens, M., Tomme, P. and Knowles, J.K., 1988. EGIII, a new endoglucanase from Trichoderma reesei: the characterization of both gene and enzyme. Gene, 63(1), pp.11-21.

[3] Jecu, L., 2000. Solid state fermentation of agricultural wastes for endoglucanase production. Industrial Crops and Products, 11(1), pp.1-5.

[4] Bandyopadhyay, S., Karmakar, M. and Ray, R.R., 2012. Increase in endoglucanase productivity and mycelial stability of Rhizopus oryzae by classical mutagenesis. Biotechnology Journal International, pp.60-72.

[5] Sami, A.J. and Shakoori, A.R., 2014. Potential of Azadirachtin and neem (Azadirachta indica) based saponins as biopesticides for in vitro insect pests cellulase (Beta-1, 4-Endoglucanase) enzyme inhibition and in vivo repellency on Tribolium castaneum. Biotechnology Journal International, pp.904-917.

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