Details
| Original language | English |
|---|---|
| Pages (from-to) | 203-209 |
| Number of pages | 7 |
| Journal | Journal of bacteriology |
| Volume | 91 |
| Issue number | 1 |
| Publication status | Published - Jan 2009 |
Abstract
Clostridium thermocellum is an anaerobic thermophilic bacterium that grows efficiently on cellulosic biomass. This bacterium produces and secretes a highly active multienzyme complex, the cellulosome, that mediates the cell attachment to and hydrolysis of the crystalline cellulosic substrate. C. thermocellum can efficiently utilize only β-1,3 and β-1,4 glucans and prefers long cellodextrins. Since the bacterium can also produce ethanol, it is considered an attractive candidate for a consolidated fermentation process in which cellulose hydrolysis and ethanol fermentation occur in a single process. In this study, we have identified and characterized five sugar ABC transporter systems in C. thermocellum. The putative transporters were identified by sequence homology of the putative solute-binding lipoprotein to known sugar-binding proteins. Each of these systems is transcribed from a gene cluster, which includes an extracellular solute-binding protein, one or two integral membrane proteins, and, in most cases, an ATP-binding protein. The genes of the five solute-binding proteins were cloned, fused to His tags, overexpressed, and purified, and their abilities to interact with different sugars was examined by isothermal titration calorimetry. Three of the sugar-binding lipoproteins (CbpB to -D) interacted with different lengths of cellodextrins (G2 to G 5), with disassociation constants in the micromolar range. One protein, CbpA, binds only cellotriose (G3), while another protein, Lbp (laminaribiose-binding protein) interacts with laminaribiose. The sugar specificity of the different binding lipoproteins is consistent with the observed substrate preference of C. thermocellum, in which cellodextrins (G 3 to G5) are assimilated faster than cellobiose.
ASJC Scopus subject areas
- Immunology and Microbiology(all)
- Microbiology
- Biochemistry, Genetics and Molecular Biology(all)
- Molecular Biology
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In: Journal of bacteriology, Vol. 91, No. 1, 01.2009, p. 203-209.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Cellodextrin and Laminaribiose ABC Transporters in Clostridium thermocellum
AU - Nataf, Yakir
AU - Yaron, Sima
AU - Stahl, Frank
AU - Lamed, Raphael
AU - Bayer, Edward A.
AU - Scheper, Thomas Helmut
AU - Sonenshein, Abraham L.
AU - Shoham, Yuval
PY - 2009/1
Y1 - 2009/1
N2 - Clostridium thermocellum is an anaerobic thermophilic bacterium that grows efficiently on cellulosic biomass. This bacterium produces and secretes a highly active multienzyme complex, the cellulosome, that mediates the cell attachment to and hydrolysis of the crystalline cellulosic substrate. C. thermocellum can efficiently utilize only β-1,3 and β-1,4 glucans and prefers long cellodextrins. Since the bacterium can also produce ethanol, it is considered an attractive candidate for a consolidated fermentation process in which cellulose hydrolysis and ethanol fermentation occur in a single process. In this study, we have identified and characterized five sugar ABC transporter systems in C. thermocellum. The putative transporters were identified by sequence homology of the putative solute-binding lipoprotein to known sugar-binding proteins. Each of these systems is transcribed from a gene cluster, which includes an extracellular solute-binding protein, one or two integral membrane proteins, and, in most cases, an ATP-binding protein. The genes of the five solute-binding proteins were cloned, fused to His tags, overexpressed, and purified, and their abilities to interact with different sugars was examined by isothermal titration calorimetry. Three of the sugar-binding lipoproteins (CbpB to -D) interacted with different lengths of cellodextrins (G2 to G 5), with disassociation constants in the micromolar range. One protein, CbpA, binds only cellotriose (G3), while another protein, Lbp (laminaribiose-binding protein) interacts with laminaribiose. The sugar specificity of the different binding lipoproteins is consistent with the observed substrate preference of C. thermocellum, in which cellodextrins (G 3 to G5) are assimilated faster than cellobiose.
AB - Clostridium thermocellum is an anaerobic thermophilic bacterium that grows efficiently on cellulosic biomass. This bacterium produces and secretes a highly active multienzyme complex, the cellulosome, that mediates the cell attachment to and hydrolysis of the crystalline cellulosic substrate. C. thermocellum can efficiently utilize only β-1,3 and β-1,4 glucans and prefers long cellodextrins. Since the bacterium can also produce ethanol, it is considered an attractive candidate for a consolidated fermentation process in which cellulose hydrolysis and ethanol fermentation occur in a single process. In this study, we have identified and characterized five sugar ABC transporter systems in C. thermocellum. The putative transporters were identified by sequence homology of the putative solute-binding lipoprotein to known sugar-binding proteins. Each of these systems is transcribed from a gene cluster, which includes an extracellular solute-binding protein, one or two integral membrane proteins, and, in most cases, an ATP-binding protein. The genes of the five solute-binding proteins were cloned, fused to His tags, overexpressed, and purified, and their abilities to interact with different sugars was examined by isothermal titration calorimetry. Three of the sugar-binding lipoproteins (CbpB to -D) interacted with different lengths of cellodextrins (G2 to G 5), with disassociation constants in the micromolar range. One protein, CbpA, binds only cellotriose (G3), while another protein, Lbp (laminaribiose-binding protein) interacts with laminaribiose. The sugar specificity of the different binding lipoproteins is consistent with the observed substrate preference of C. thermocellum, in which cellodextrins (G 3 to G5) are assimilated faster than cellobiose.
UR - http://www.scopus.com/inward/record.url?scp=58149479219&partnerID=8YFLogxK
U2 - 10.1128/JB.01190-08
DO - 10.1128/JB.01190-08
M3 - Article
C2 - 18952792
AN - SCOPUS:58149479219
VL - 91
SP - 203
EP - 209
JO - Journal of bacteriology
JF - Journal of bacteriology
SN - 0021-9193
IS - 1
ER -