Primary structure of O‐linked carbohydrate chains in the cellulosome of different Clostridium thermocellum strains

The cell‐free forms of the multiple cellulase‐containing protein complex (cellulosome), isolated from the celluloytic bacterium Clostridium thermocellum strains YS, ATCC 27405 and LQRI, have a total carbohydrate content of 5–7% (by mass), consisting of O‐linked oligosaccharide chains. The carbohydrate chains were liberated by alkaline‐borohydride treatment and fractionated as oligosaccharide alditols via gel‐permeation chromatography and HPLC. The fractions were investigated by 500‐MHz ¹H‐NMR spectroscopy in combination with monosaccharide and methylation analysis and with fast‐atom‐bombardment mass spectrometry (FAB‐MS). In addition to the previously described major oligosaccharide, (Formula Presented.) [Gerwig, G. J., de Waard, P., Kamerling, J. P., Vliegenthart, J. F. G., Morgenstern, E., Lamed, R. & Bayer, E. A. (1989) J. Biol. Chem. 264, 1027 – 10351, the following partial structures of this compound could be established: (Formula Presented.) Cell‐free and cell‐associated forms of the cellulosome of C. thermocellum, as determined for strain YS, have the same oligosaccharide pattern. Based on the oligosaccharide structures, a biosynthetic pathway is suggested.