Improvement of the Cellulolytic Activity of Trichoderma reesei Endoglucanase IV with an Additional Catalytic Domain

Abstract

The modular structure of the T. reesei endoglucanase IV (EGIV) was reconstructed by fusing EGIV with an additional catalytic module (EGIV-CM). The genes eg4 and eg4-cm were obtained through RT-PCR and gene fusion, and were respectively expressed in recombinant Pichia strains (P. pastoris EGIV1 and P. pastoris EGIV-CM1). The CMC activities of cultivation supernatant of P. pastoris EGIV1 and P. pastoris EGIV-CM1 were 2.4 U/ml and 4.3 U/ml, respectively. Modification of the EGIV structure with an additional catalytic module improved the specific activity about 4-fold.

The First Structure of a Glycoside Hydrolase Family 61 Member, Cel61B from Hypocrea jecorina, at 1.6 Å Resolution

“…6,8,9 We have seen low levels of endoglucanase activity in H. jecorina Cel61B (data not shown), similar to those reported for Cel61A. However, the Cel61B structure does not allow us to easily identify a suitable catalytic center or a typical carbohydratebinding platform.…”

“…Low endoglucanase activities have been observed for H. jecorina Cel61A when homologously expressed 8 and when expressed in yeast 6 or in Pichia pastoris. 9 Cel61A from Aspergillus kawachii (AB055432/Q96WQ9) has also been reported to be an endoglucanase. 10 Currently, there are more than 70 CAZy entries for GH family 61 † (Ref.…”

Chemical modification of Aspergillus niger β-glucosidase and its catalytic properties

“…An efficient cellulose hydrolysis requires a stable β-glucosidase for the utilization of abundant cellulosic waste material on an industrial scale ( Rashid and Siddiqui, 1996 ). There are several major and principally different routes to obtain cellulases with improved stability properties to date: (a) by selecting organisms living in appropriate extreme environments ( Huang et al , 2005 ; Kubartova et al , 2007 ), (b) by gene recombination and genetic engineering ( Liu et al , 2006 ; Kim et al , 2007 ), (c) by immobilization ( Sinegania et al , 2005 ; Singh et al , 2011 ), and (d) by chemical modification ( Yang et al , 2009 ; Cai et al , 2012 ). Chemical modification is the process of covalent attachment of special groups of modifiers to the side-chain group of certain amino-acid residues in the enzyme.…”

Chemical modification of β-endoglucanase from Trichoderma viridin by methanol and determination of the catalytic functional groups

“…Cellulases are enzymes that hydrolyze cellulose (beta-1,4-glucan or beta D-glucosidic linkages) resulting in the formation of glucose, cellobiose, cellooligosaccharides, and the like (Su et al, 2010). Cellulases have been There are several major and principally different routes to obtain cellulases with improved stability properties to date: (1) by selection from organisms living in appropriate extreme environments (Kashima et al, 2005;Huang et al, 2005;Kubartova et al, 2007), (2) by gene recombination and genetic engineering (Valenzuela et al, 2006;Feng et al, 2007;Kim et al, 2007;Brune, 2007;Schmidt, 2007;Liu et al, 2006), (3) by immobilization (Wu et al, 2005;Sinegania et al, 2005;Dong et al, 2008), and (4) by chemical modification (Kwinam et al, 2002;Yang et al, 2009). The main strategies of aforementioned ways are based on changing the cellulases' molecule structure or living environments.…”