Organization and distribution of the cellulosome in Clostridium thermocellum.
The properties of the cellulosome (the cellulose-binding, multicellulase-containing protein complex) in Clostridium thermocellum were examined by comparing the cellulase systems derived from the wild type and an adherence-defective mutant. The growth conditions--specifically, growth either on cellulose (Avicel) or on cellobiose as insoluble or soluble carbon sources, respectively--were found to be critical to the distribution of the cellulosome in the mutant system: the cellobiose-grown mutant (in contrast to the wild type) lacked the cellulosome on its surface and produced only minor quantities of the extracellular cellulosome accompanied by other relatively low-molecular-weight cellulases. The polypeptide composition of the respective purified cellulosome was dependent on the nature of the carbon source and was similar for both wild-type and mutant cells. Ultrastructural analysis revealed the presence of novel polycellulosomal protuberances on the cell surface of the cellobiose-grown wild type which were absent in the mutant.
D002462:Cell Membrane / Q000648:ultrastructure; D002480:Cellulase / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D003013:Clostridium / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008854:Microscopy, Electron; D008970:Molecular Weight; D009154:Mutation; D011485:Protein Binding; D013045:Species Specificity
D002482:Cellulose; D002480:Cellulase