Transcriptional regulation of an endoglucanase and a cellodextrinase gene in Ruminococcus flavefaciens FD-1

Wang, Wenyen; Reid, Sharon J.; Thomson, Jennifer A.

doi:10.1099/00221287-139-6-1219

Cited by 31 publications

(24 citation statements)

References 35 publications

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“…Moreover, it was reported that Clostridium thermocellum assimilates cellopentaose preferentially during growth on cellulose (57). In addition, the transcription of endoglucanase genes is induced by cellotriose rather than cellobiose in Ruminococcus flavefaciens (56). These findings indicate the presence of selective assimilation and response mechanisms for specific cellooligosaccharides in these bacteria.…”

mentioning

confidence: 56%

Cellotriose and Cellotetraose as Inducers of the Genes Encoding Cellobiohydrolases in the Basidiomycete Phanerochaete chrysosporium

Suzuki

Igarashi

Samejima

2010

Appl Environ Microbiol

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The wood decay basidiomycete Phanerochaete chrysosporium produces a variety of cellobiohydrolases belonging to glycoside hydrolase (GH) families 6 and 7 in the presence of cellulose. However, no inducer of the production of these enzymes has yet been identified. Here, we quantitatively compared the transcript levels of the genes encoding GH family 6 cellobiohydrolase (cel6A) and GH family 7 cellobiohydrolase isozymes (cel7A to cel7F/G) in cultures containing glucose, cellulose, and cellooligosaccharides by real-time quantitative PCR, in order to evaluate the transcription-inducing effect of soluble sugars. Upregulation of transcript levels in the presence of cellulose compared to glucose was observed for cel7B, cel7C, cel7D, cel7F/G, and cel6A at all time points during cultivation. In particular, the transcription of cel7C and cel7D was strongly induced by cellotriose or cellotetraose. The highest level of cel7C transcripts was observed in the presence of cellotetraose, whereas the highest level of cel7D transcripts was found in the presence of cellotriose, amounting to 2.7 ؋ 10 6 and 1.7 ؋ 10 6 copies per 10 5 actin gene transcripts, respectively. These numbers of cel7C and cel7D transcripts were higher than those in the presence of cellulose. In contrast, cellobiose had a weaker transcription-inducing effect than either cellotriose or cellotetraose for cel7C and had little effect in the case of cel7D. These results indicate that cellotriose and cellotetraose, but not cellobiose, are possible natural cellobiohydrolase gene transcription inducers derived from cellulose.

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confidence: 56%

Cellotriose and Cellotetraose as Inducers of the Genes Encoding Cellobiohydrolases in the Basidiomycete Phanerochaete chrysosporium

Suzuki

Igarashi

Samejima

2010

Appl Environ Microbiol

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“…Doerner et al (164) have reported that the celA and celC genes were expressed constitutively while expression of the celB and celD was induced by cellulose. However, Wang et al (721) have reported that the cellodextrinase celA and celE genes are both induced by cellulose.…”

Section: Molecular Biology Of Cellulase Enzymesmentioning

confidence: 99%

Microbial Cellulose Utilization: Fundamentals and Biotechnology

Lynd

Weimer

Zyl³

et al. 2002

Microbiol Mol Biol Rev

4,047

2,868

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Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial cellulose utilization, kinetics of microbial cellulose utilization, and contrasting features compared to soluble substrate kinetics. A biological perspective on processing cellulosic biomass is presented, including features of pretreated substrates and alternative process configurations. Organism development is considered for “consolidated bioprocessing” (CBP), in which the production of cellulolytic enzymes, hydrolysis of biomass, and fermentation of resulting sugars to desired products occur in one step. Two organism development strategies for CBP are examined: (i) improve product yield and tolerance in microorganisms able to utilize cellulose, or (ii) express a heterologous system for cellulose hydrolysis and utilization in microorganisms that exhibit high product yield and tolerance. A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts

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“…On the other hand, there are many reports of single-domain endoglucanases from R. flavefaciens and R. albus that are smaller than 50 kDa (30,33,40,41,42). This may suggest that not all cellulases are cellulosome associated in ruminococci.…”

Section: Discussionmentioning

confidence: 92%

EndB, a Multidomain Family 44 Cellulase from Ruminococcus flavefaciens 17, Binds to Cellulose via a Novel Cellulose-Binding Module and to Another R. flavefaciens Protein via a Dockerin Domain

Rincón¹,

McCrae²,

Kirby³

et al. 2001

Appl Environ Microbiol

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The mechanisms by which cellulolytic enzymes and enzyme complexes in Ruminococcus spp. bind to cellulose are not fully understood. The product of the newly isolated cellulase gene endB from Ruminococcus flavefaciens 17 was purified as a His-tagged product after expression in Escherichia coli and found to be able to bind directly to crystalline cellulose. The ability to bind cellulose is shown to be associated with a novel cellulose-binding module (CBM) located within a region of 200 amino acids that is unrelated to known protein sequences. EndB (808 amino acids) also contains a catalytic domain belonging to glycoside hydrolase family 44 and a C-terminal dockerin-like domain. Purified EndB is also shown to bind specifically via its dockerin domain to a polypeptide of ca. 130 kDa present among supernatant proteins from Avicel-grown R. flavefaciens that attach to cellulose. Cellulolytic Ruminococcus spp. play an important role in the degradation of plant cell wall polysaccharides in the rumen and hindgut of mammals (5,15,20). Early biochemical and microscopic evidence indicated that their plant cell wall-degrading enzymes are organized into high-molecular-weight complexes on the cell surface (22,24,43). Analysis of cloned polysaccharidase genes has, however, produced somewhat conflicting evidence concerning the molecular organization of these enzymes, and the mechanisms by which they might attach to their substrate and to the cell surface have thus remained unclear. Many of the cellulase genes first isolated from R. flavefaciens and R. albus (7,18,30,33,40,41) were reported to encode single domain enzymes smaller than 50 kDa that carry no obvious substrate binding domains, and no regions that might be responsible for the types of protein-protein interactions that are found, for example, in the assembly of cellulosome complexes from Clostridium spp. (3, 4, 9). On the other hand, it has been known for some time that xylanases from R. flavefaciens display complex multidomain organization (11, 45). Furthermore, the endoglucanase EndA from R. flavefaciens 17 was shown to be a multidomain enzyme carrying an 80-amino-acid dockerin-like region that is also present in three xylanases and an esterase from the same strain (2, 19). Dockerin-like regions have also been reported recently in multidomain endoglucanases from R. albus F40 (29, 30). Since dockerins are responsible for the assembly of cellulosome complexes via specific dockerin-cohesin interactions in Clostridium species (3,4,17,31,34), this provides a strong indication that complexes resembling cellulosomes may be involved in the organization of many plant cell wall-degrading enzymes in ruminococci. In support of this, two linked genes that encode structural proteins containing cohesin domains have recently been identified in R. flavefaciens 17 (8). Cellulosome organization provides one potential mechanism for binding of cellulolytic enzymes to their substrate since cellulosomal scaffolding proteins from clostridia carry cellulose-binding modules (CBMs) (4, 39). On t...

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Transcriptional regulation of an endoglucanase and a cellodextrinase gene in Ruminococcus flavefaciens FD-1

Cited by 31 publications

References 35 publications

Cellotriose and Cellotetraose as Inducers of the Genes Encoding Cellobiohydrolases in the Basidiomycete Phanerochaete chrysosporium

Cellotriose and Cellotetraose as Inducers of the Genes Encoding Cellobiohydrolases in the Basidiomycete Phanerochaete chrysosporium

Microbial Cellulose Utilization: Fundamentals and Biotechnology

EndB, a Multidomain Family 44 Cellulase from Ruminococcus flavefaciens 17, Binds to Cellulose via a Novel Cellulose-Binding Module and to Another R. flavefaciens Protein via a Dockerin Domain

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