Substrate-Induced Production and Secretion of Cellulases by Clostridium acetobutylicum
AUTOR(ES)
López-Contreras, Ana M.
FONTE
American Society for Microbiology
RESUMO
Clostridium acetobutylicum ATCC 824 is a solventogenic bacterium that grows heterotrophically on a variety of carbohydrates, including glucose, cellobiose, xylose, and lichenan, a linear polymer of β-1,3- and β-1,4-linked β-d-glucose units. C. acetobutylicum does not degrade cellulose, although its genome sequence contains several cellulase-encoding genes and a complete cellulosome cluster of cellulosome genes. In the present study, we demonstrate that a low but significant level of induction of cellulase activity occurs during growth on xylose or lichenan. The celF gene, located in the cellulosome-like gene cluster and coding for a unique cellulase that belongs to glycoside hydrolase family 48, was cloned in Escherichia coli, and antibodies were raised against the overproduced CelF protein. A Western blot analysis suggested a possible catabolite repression by glucose or cellobiose and an up-regulation by lichenan or xylose of the extracellular production of CelF by C. acetobutylicum. Possible reasons for the apparent inability of C. acetobutylicum to degrade cellulose are discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=520844Documentos Relacionados
- Substrate-induced conformational change in a trimeric ornithine transcarbamoylase
- Substrate-induced membrane association of phosphatidylserine synthase from Escherichia coli.
- Transcriptional bias: a non-Lamarckian mechanism for substrate-induced mutations.
- Crystal Structures of Human SIRT3 Displaying Substrate-induced Conformational Changes
- Human immunodeficiency virus reverse transcriptase substrate-induced conformational changes and the mechanism of inhibition by nonnucleoside inhibitors.
