Homology between cellulase genes of Trichoderma reesei: complete nucleotide sequence of the endoglucanase I gene

Cellulose-binding domains (CBDs) form distinct functional units of most cellulolytic enzymes. We have compared the cellulose-binding affinities of the CBDs of ceilobiohydrolase 1 (CBHI) and endoglucanase I (EGI) from the fungus Trichoderma reeseL The CBD of EGI had significantly higher affinity than that of CBHI. Four variants of the CBHI CBD were made in order to identify the residues responsible for the increased affinity in EGI. Most of the difference could be ascribed to a replacement of a tyrosine by a tryptophan on the flat cellulose-binding face.

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“…2. Sequence alignment of the CBHI and EGI CBDs [21,22]. Amino acids strictly conserved in homologous sequences are shown in bold.…”

Section: Resultsmentioning

confidence: 99%

The difference in affinity between two fungal cellulose‐binding domains is dominated by a single amino acid substitution

et al. 1995

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“…EG1 and CBH1 have significant homology (45% identity, Penttila et al, 1986), belong to the same family (Cel7), and both use a retaining mechanism. The active site of EG1 is a groove rather than a tunnel (Henriksson et al, 1996), allowing glucan chains to be cleaved randomly to two shorter chains resulting in a rapid decrease in DP (KlemanLeyer et al, 1992(KlemanLeyer et al, , 1994Srisodsuk et al, 1998;Whitaker, 1957;Selby, 1961;Wood and McCrae, 1978).…”

Section: Trichoderma Reesei Cellulase Systemmentioning

confidence: 99%

Toward an aggregated understanding of enzymatic hydrolysis of cellulose: Noncomplexed cellulase systems

Zhang

Lynd

2004

Biotech & Bioengineering

1,650

1,284

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Information pertaining to enzymatic hydrolysis of cellulose by noncomplexed cellulase enzyme systems is reviewed with a particular emphasis on development of aggregated understanding incorporating substrate features in addition to concentration and multiple cellulase components. Topics considered include properties of cellulose, adsorption, cellulose hydrolysis, and quantitative models. A classification scheme is proposed for quantitative models for enzymatic hydrolysis of cellulose based on the number of solubilizing activities and substrate state variables included. We suggest that it is timely to revisit and reinvigorate functional modeling of cellulose hydrolysis, and that this would be highly beneficial if not necessary in order to bring to bear the large volume of information available on cellulase components on the primary applications that motivate interest in the subject. B

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“…At the bottom line an f or an r indicates if the residue side chain is exposed on the flat or the rough face, respectively, in the CBHI CBD. CBDs are from: T. reesei CBHl (Shoemaker et al, 1983), T. reesei CBHll (Teeri et al, 1987), T. reeseiEGI (Penttila et al, 1986), 7: reesei EGII (Saloheimo et al, 1988), T. viridae CBH (Cheng et al, 1990), Agaricus bisporus CELl (Raguz et al, 1992), A. bisporus CEL3 (Chow et al, 1994), Penicillium janthinellum CBHI (Koch et al, 1993), Phanerochaete chrysosporium CBHI ( Sims et al, 1988), Humicola grisea CBHI (Azevedo et al, 1990). H. insolens EGV (Rasmussen et al, 1991), and T. reesei EGV (Saloheimo et al, 1994).…”

Section: Choice Of the Engineered Peptidesmentioning

confidence: 99%

Identification of functionally important amino acids in the cellulose‐binding domain of Trichoderma reesei cellobiohydrolase I

et al. 1995

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Cellobiohydrolase I (CBHI) of Trichoderma reesei has two functional domains, a catalytic core domain and a cellulose binding domain (CBD). The structure of the CBD reveals two distinct faces, one of which is flat and the other rough. Several other fungal cellulolytic enzymes have similar two-domain structures, in which the CBDs show a conserved primary structure. Here we have evaluated the contributions of conserved amino acids in CBHI CBD to its binding to cellulose. Binding isotherms were determined for a set of six synthetic analogues in which conserved amino acids were substituted. Two-dimensional NMR spectroscopy was used to assess the structural effects of the substitutions by comparing chemical shifts, coupling constants, and NOES of the backbone protons between the wild-type CBD and the analogues. In general, the structural effects of the substitutions were minor, although in some cases decreased binding could clearly be ascribed to conformational perturbations. We found that at least two tyrosine residues and a glutamine residue on the flat face were essential for tight binding of the CBD to cellulose. A change on the rough face had only a small effect on the binding and it is unlikely that this face interacts with cellulose directly.

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Homology between cellulase genes of Trichoderma reesei: complete nucleotide sequence of the endoglucanase I gene

Cited by 280 publications

References 42 publications

The difference in affinity between two fungal cellulose‐binding domains is dominated by a single amino acid substitution

The difference in affinity between two fungal cellulose‐binding domains is dominated by a single amino acid substitution

Toward an aggregated understanding of enzymatic hydrolysis of cellulose: Noncomplexed cellulase systems

Identification of functionally important amino acids in the cellulose‐binding domain of Trichoderma reesei cellobiohydrolase I

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