5g56

Publication Abstract from PubMed

The cellulosome, a highly elaborate extracellular multi-enzyme complex of cellulases and hemicellulases, is responsible for the degradation of plant cell walls. The xylanase CtXyl5A (Cthe_2193) is a multimodular arabinoxylanase which is one of the largest components of the Clostridium thermocellum cellulosome. The N-terminal catalytic domain of CtXyl5A, which is a member of glycoside hydrolase family 5 (GH5), is responsible for the hydrolysis of arabinoxylans. Appended after it are three noncatalytic carbohydrate-binding modules (CBMs), which belong to families 6 (CBM6), 13 (CBM13) and 62 (CBM62). In addition, CtXyl5A has a fibronectin type III-like (Fn3) module preceding the CBM62 and a type I dockerin (DOK) module following it which allows the enzyme to be integrated into the cellulosome through binding to a cohesin module of the protein scaffold CipA. Crystals of the pentamodular enzyme without the DOK module at the C-terminus, with the domain architecture CtGH5-CBM6-CBM13-Fn3-CBM62, have been obtained. The structure of this pentamodular xylanase has been determined by molecular replacement to a resolution of 2.64 A using coordinates of CtGH5-CBM6, Fn3 and CBM62 from the PDB as search models.

Purification, crystallization and preliminary X-ray characterization of the pentamodular arabinoxylanase CtXyl5A from Clostridium thermocellum.,Bras JL, Correia MA, Romao MJ, Prates JA, Fontes CM, Najmudin S Acta Crystallogr Sect F Struct Biol Cryst Commun. 2011 Jul 1;67(Pt 7):833-6. doi:, 10.1107/S1744309111020823. Epub 2011 Jun 30. PMID:21795807^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.