Poster (Painel)
| 68-1 | Effect of pH and temperature on the global compactness, structure and activity of cellobiohydrolase 1 from Trichoderma harzianum IOC 3844 | | Authors: | Wanius Garcia (CCNH/UFABC - Universidade Federal do ABC (UFABC)) ; Francieli Colussi (IFSC/USP - Instituto de Física de São Carlos) ; Flavio Rodolfo Rosseto (IFSC/USP - Instituto de Física de São Carlos) ; Bruno Luan Soares de Mello (IFSC/USP - Instituto de Física de São Carlos) ; Mario de Oliveira Neto (IFSC/USP - Instituto de Física de São Carlos) ; Igor Polikarpov (IFSC/USP - Instituto de Física de São Carlos) |
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Wanius Garcia1, Francieli Colussi2, Flávio Rodolfo Rosseto2, Bruno Luan Soares de Mello2, Mário de Oliveira Neto2 and Igor Polikarpov2 ഀ
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1Centro de Ciências Naturais e Humanas (CCNH), Universidade Federal do ABC (UFABC), Santo André, SP, Brazil. ഀ
2Instituto de Física de São Carlos (IFSC), Universidade de São Paulo (USP). São Carlos, SP, Brazil. ഀ
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Cellulases produced by filamentous fungi are widely used in biotechnological applications, including biomass depolymerization and second generation bioethanol production. However, stability of cellulases in defined pH and temperature ranges sets limits to their industrial utilizations. Here, we examine the effects of pH and temperature on the secondary and tertiary structures, compactness and enzymatic activity of a filamentous fungus T. harzianum cellobiohydrolase 1 IOC-3844 (ThCBH1) using a number of biophysical and biochemical techniques. Our results show that pH and temperature perturbations affect ThCBH1 stability by two different mechanisms. Variations of pH modify protonation of the enzyme residues, directly affecting its activity, but leading to structural destabilization only at extreme pH limits. Temperature, on the other hand, has direct influence on mobility, fold and compactness of the enzyme, causing irreversible unfolding of ThCBH1 just above optimum temperature limit. Finally, we demonstrate that incubation with the product of reaction and competitive inhibitor, cellobiose, increase significantly thermal stability of ThCBH1. Thus, our studies might provide insights into understanding, at molecular level, of the interplay between structure and activity of ThCBH1 at different pH and temperature conditions, which can be useful for possible biotechnological applications of the enzyme as bioethanol production. ഀ
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This work was supported by FAPESP, CNPq and CAPES. ഀ
Keyword: Trichoderma harzianum, bioethanol, cellobiohydrolase, cellulose, cellobiose |