Properties and Mutation Analysis of the CelK Cellulose-Binding Domain from the
            <i>Clostridium thermocellum</i>
            Cellulosome

Kataeva, Irina; Seidel, R.D.; Li, Xinliang; Ljungdahl, Lars G.

doi:10.1128/jb.183.5.1552-1559.2001

Cited by 28 publications

(23 citation statements)

References 56 publications

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“…In addition to the 10-fold difference for AS CBH1 noted above for BMCC as compared to Avicel, studies using unfractionated T. reesei cellulase have reported a 3-fold higher cellulase adsorption capacity for Solka Floc SW40 compared to Avicel (Steiner et al, 1988), and a 20-folder higher capacity for PASC compared to Avicel Morag et al, 1995). Accessible area in the order Avicel < BMCC < PASC is also supported by data from the CBMs isolated from C. fimi (Ong et al, 1993) and from CelK of C. thermocellum (Kataeva et al, 2001).…”

Section: Spatial Analysis Of Adsorption and Inferred Accessibility Ofsupporting

confidence: 48%

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

Zhang

Lynd

2004

Biotech & Bioengineering

1,646

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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Section: Spatial Analysis Of Adsorption and Inferred Accessibility Ofsupporting

confidence: 48%

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

Zhang

Lynd

2004

Biotech & Bioengineering

1,646

1,284

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“…The family 4 CBD is generally not essential for catalytic function, except for C. cellulolyticum CelE (94). The family 4 CBD of the C. thermocellum CelK has a binding capacity of ϳ4 mmol/g of cellulose (154), similar to those of the family 3 CBDs which have been characterized. It is interesting that LicA, a noncellulosomal C. thermocellum ␤-1,3-glucanase, has four family 4 CBDs at its C-terminal end (86).…”

Section: Cellulose-binding Domainmentioning

confidence: 67%

Cellulase, Clostridia, and Ethanol

Demain

Newcomb

2005

Microbiol Mol Biol Rev

806

579

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SUMMARY Biomass conversion to ethanol as a liquid fuel by the thermophilic and anaerobic clostridia offers a potential partial solution to the problem of the world's dependence on petroleum for energy. Coculture of a cellulolytic strain and a saccharolytic strain of Clostridium on agricultural resources, as well as on urban and industrial cellulosic wastes, is a promising approach to an alternate energy source from an economic viewpoint. This review discusses the need for such a process, the cellulases of clostridia, their presence in extracellular complexes or organelles (the cellulosomes), the binding of the cellulosomes to cellulose and to the cell surface, cellulase genetics, regulation of their synthesis, cocultures, ethanol tolerance, and metabolic pathway engineering for maximizing ethanol yield.

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“…Two aspartic acids, a histidine, and a glutamic acid, which have been confirmed as the catalytic amino acids in C. thermocellum (49), were conserved in four identical regions as the nucleophile and the proton donor. The domain organization of EngO (CBM4-Ig-GH9) compared with those of closely related cellulases such as C. cellulolyticum CelE (14), C. thermocellum CelK (27), and Streptomyces reticuli Cel1 (38) reveals that conservation among catalytic cores is greater than conservation among CBM4, indicating either a lower level of evolutionary pressure on these last domains or changes in function and specificities. In addition, EngO exhibits a common domain organization among family 9 endoglucanases such as EngK and EngM in C. cellulovorans, sharing the same modular structure except lacking the dockerin domain as a noncellulosomal enzyme.…”

Section: Resultsmentioning

confidence: 99%

Molecular Cloning and Transcriptional and Expression Analysis of engO , Encoding a New Noncellulosomal Family 9 Enzyme, from Clostridium cellulovorans

et al. 2005

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Clostridium cellulovorans produces a major noncellulosomal family 9 endoglucanase EngO. A genomic DNA fragment (40 kb) containing engO and neighboring genes was cloned. The nucleotide sequence contained reading frames for endoglucanase EngO, a putative response regulator, and a putative sensor histidine kinase protein. The engO gene consists of 2,172 bp and encodes a protein of 724 amino acids with a molecular weight of 79,474. Northern hybridizations revealed that the engO gene is transcribed as a monocistronic 2.6-kb mRNA. 5 RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) PCR analysis indicated that the single transcriptional start site of engO was located 264 bp upstream from the first nucleotide of the translation initiation codon. Alignment of the engO promoter region provided evidence for highly conserved sequences that exhibited strong similarity to the A consensus promoter sequences of gram-positive bacteria. EngO contains a typical N-terminal signal peptide of 28 amino acid residues, followed by a 149-amino-acid sequence which is homologous to the family 4-9 carbohydrate-binding domain. Downstream of this domain was an immunoglobulin-like domain of 89 amino acids. The C terminus contains a family 9 catalytic domain of glycosyl hydrolase. Mass spectrometry analysis of EngO was in agreement with that deduced from the nucleotide sequence. Expression of engO mRNA increased from early to middle exponential phase and decreased during the early stationary phase. EngO was highly active toward carboxymethyl cellulose but showed no activity towards xylan. It was optimally active at 40 to 50°C and pH 5 to 6. The analysis of the products from the cellulose hydrolysis through thin-layer chromatography indicated its endoglucanase activity.Clostridium cellulovorans ATCC 35296 (43) is a mesophilic, anaerobic, spore-forming bacterium which can utilize cellulose and other plant cell wall polysaccharides (9, 48). C. cellulovorans produces an extracellular enzyme complex (called a cellulosome) containing a variety of cellulolytic subunits attached to the nonenzymatic scaffolding protein CbpA (10,39,42). All cellulosomal enzymatic subunits contain a twice-repeated sequence called the dockerin domain that is lacking in noncellulosomal cellulolytic enzymes (1).C. cellulovorans also produces noncellulosomal enzymes such as EngD (17), EngF (40), ArfA (28), and BgaA (28) that work synergistically with the cellulosomal enzymes (28). Thus far, 12 cellulosomal enzymatic subunits and 4 noncellulosomal enzymes from C. cellulovorans have been sequenced, including cellulases, xylanases, a mannanase, and a pectate lyase from eight different glycoside hydrolase families (9). Among the cellulosomal cellulase genes identified, five encode family 9 glycoside hydrolases, i.e., EngK (48), EngM (48), EngY (46), EngH (48), and EngL (45).The nucleotide sequence, expression, and the characterization of the engO gene and its product EngO, a family 9 noncellulosomal endoglucanase from C. cellulovorans, are reported in this paper. A ...

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Properties and Mutation Analysis of the CelK Cellulose-Binding Domain from the Clostridium thermocellum Cellulosome

Cited by 28 publications

References 56 publications

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

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

Cellulase, Clostridia, and Ethanol

Molecular Cloning and Transcriptional and Expression Analysis of engO , Encoding a New Noncellulosomal Family 9 Enzyme, from Clostridium cellulovorans

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