This domain binds to cellulose and to bacterial cell walls. It is found in glycosyl hydrolases and in scaffolding proteins of cellulosomes (multiprotein glycosyl hydrolase complexes). In the cellulosome it may aid cellulose degradation by anchoring the cellulosome to the bacterial cell wall and by binding it to its substrate [1]. This domain has an Ig-like fold [2].

1: Hydrophilic domains of scaffolding protein CbpA promote glycosyl hydrolase activity and localization of cellulosomes to the cell surface of Clostridium cellulovorans. Kosugi A, Amano Y, Murashima K, Doi RH; J Bacteriol. 2004;186:6351-6359. PMID:15375114

2: Solution structure of the module X2 1 of unknown function of the cellulosomal scaffolding protein CipC of Clostridium cellulolyticum. Mosbah A, Belaich A, Bornet O, Belaich JP, Henrissat B, Darbon H; J Mol Biol 2000;304:201-217. PMID:11080456