1g1k | pdb_00001g1k
COHESIN MODULE FROM THE CELLULOSOME OF CLOSTRIDIUM CELLULOLYTICUM
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Overview
In the assembly of the Clostridium cellulolyticum cellulosome, the, multiple cohesin modules of the scaffolding protein CipC serve as, receptors for cellulolytic enzymes which bear a dockerin module. The X-ray, structure of a type I C. cellulolyticum cohesin module (Cc-cohesin) has, been solved using molecular replacement, and refined at 2.0 A resolution., Despite a rather low sequence identity of 32 %, this module has a fold, close to those of the two Clostridium thermocellum cohesin (Ct-cohesin), modules whose 3D structures have been determined previously. Cc-cohesin, forms a dimer in the crystal, as do the two Ct-cohesins. We show here that, the dimer exists in solution and that addition of dockerin-containing, proteins dissociates the dimer. This suggests that the dimerization, interface and the cohesin/dockerin interface may overlap. The nature of, the overall surface and of the dimer interface of Cc-cohesin differ, notably from those of the Ct-cohesin modules, being much less polar, and, this may explain the species specificity observed in the cohesin/dockerin, interaction of C. cellulolyticum and C. thermocellum. We have produced a, topology model of a C. cellulolyticum dockerin and of a, Cc-cohesin/dockerin complex using homology modeling and available, biochemical data. Our model suggests that a special residue pair, already, identified in dockerin sequences, is located at the center of the cohesin, surface putatively interacting with the dockerin.
About this Structure
1G1K is a Single protein structure of sequence from Clostridium cellulolyticum. Full crystallographic information is available from OCA.
Reference
Crystal structure of a cohesin module from Clostridium cellulolyticum: implications for dockerin recognition., Spinelli S, Fierobe HP, Belaich A, Belaich JP, Henrissat B, Cambillau C, J Mol Biol. 2000 Nov 24;304(2):189-200. PMID:11080455
Page seeded by OCA on Sun Nov 25 00:40:03 2007
