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The basidiomycete Coprinopsis cinerea produces the glycoside hydrolase family 6 enzyme CcCel6C at low and constitutive levels. CcCel6C exhibits unusual cellobiohydrolase activity; it hydrolyses carboxymethyl cellulose, which is a poor substrate for typical cellobiohydrolases. Here, we determined the crystal structures of CcCel6C unbound and in complex with p‐nitrophenyl β‐d‐cellotrioside and cellobiose. CcCel6C consists of a distorted seven‐stranded β/α barrel and has an enclosed tunnel, which is observed in other cellobiohydrolases from ascomecetes Hypocrea jecorina (HjeCel6A) and Humicola insolens (HinCel6A). In HjeCel6A and HinCel6A, ligand binding produces a conformational change that narrows this tunnel. In contrast, the tunnel remains wide in CcCel6C and the conformational change appears to be less favourable than in HjeCel6A and HinCel6A. The ligand binding cleft for subsite −3 of CcCel6C is also wide and is rather similar to that of endoglucanase. These results suggest that the open tunnel and the wide cleft are suitable for the hydrolysis of carboxymethyl cellulose.

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A block copolymer of cellulose and polystyrene (PS) was synthesized through atom transfer radical polymerization. Macroinitiators (MIs) were prepared by introducing 2-chloroacetamide to the reducing end of cellulose (degree of polymerization¼20, 50, 250). Subsequently, MIs were copolymerized with styrene monomer in a system of N,N,N ¢,N 00 ,N 00 -pentamethyldiethylenetriamine/CuCl or CuBr/ascorbic acid at 130 1C. The resulting copolymers were characterized by 1 H nuclear magnetic resonance and size-exclusion chromatography. The kinetic study indicated that the polymerization was controllable. The efficacy of copolymers in compatibilizing an immiscible cellulose/PS blend was confirmed by microscopic observation. The mechanism of thermal and thermo-oxidative decomposition of the blend was investigated by thermogravimetry.

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