Interactions of the CelS binding ligand with various receptor domains of the Clostridium thermocellum cellulosomal scaffolding protein, CipA.
AUTOR(ES)
Lytle, B
RESUMO
The Clostridium thermocellum cellulosomal scaffolding protein, CipA, acts as an anchor on the cellulose surface for the various catalytic subunits of the cellulosome, a large extracellular cellulase complex. CipA contains nine repeated domains that serve as receptors for the cellulosomal catalytic subunits, each of which carries a conserved, duplicated ligand sequence (DS). Four representative CipA receptor domains with sequence dissimilarity were cloned and expressed in Escherichia coli. The interaction of these cloned receptor domains with the duplicated ligand sequence of CelS (expressed as a thioredoxin fusion protein, TRX-DSCelS), was studied by nondenaturing polyacrylamide gel electrophoresis. TRX-DSCelS formed a stable complex with each of the four receptor domains, indicating that CelS, the most abundant cellulosomal catalytic subunit, binds nonselectively to all of the CipA receptors. Conversely, the duplicated sequence of CipA (in the form of TRX-DSCipA), which is homologous to that of CelS, did not bind to any of the receptors under the experimental conditions.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=177785Documentos Relacionados
- The anchorage function of CipA (CelL), a scaffolding protein of the Clostridium thermocellum cellulosome.
- Regulation of the Cellulosomal celS (cel48A) Gene of Clostridium thermocellum Is Growth Rate Dependent
- Recognition specificity of the duplicated segments present in Clostridium thermocellum endoglucanase CelD and in the cellulosome-integrating protein CipA.
- Organization of a Clostridium thermocellum gene cluster encoding the cellulosomal scaffolding protein CipA and a protein possibly involved in attachment of the cellulosome to the cell surface.
- A new type of cohesin domain that specifically binds the dockerin domain of the Clostridium thermocellum cellulosome-integrating protein CipA.