Prev. Article Next Article Table of Contents

Article

Enzymatic Polymerization to Novel Polysaccharides Having a Glucose-N-acetylglucosamine Repeating Unit, a Cellulose−Chitin Hybrid Polysaccharide

Supporting Info

Shiro Kobayashi,*^†^§ Akira Makino,^† Hironori Matsumoto,^† Shigeru Kunii,^† Masashi Ohmae,^† Toshitsugu Kiyosada,^‡ Ken Makiguchi,^‡ Akira Matsumoto,^‡ Michinobu Horie,^‡ and Shin-Ichiro Shoda^‡

Department of Materials Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan, and Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan

Biomacromolecules, 2006, 7 (5), pp 1644–1656

DOI: 10.1021/bm060094q

Publication Date (Web): April 8, 2006

Tel/FAX: +81−75−724−7688. E-mail: kobayash@kit.ac.jp.

†

Kyoto University.

Present address: R&D Center for Bio-based Materials, Kyoto Institute of Technology, Kyoto 606-8585, Japan.

‡

Tohoku University.

Abstract

A cellulose−chitin hybrid polysaccharide having alternatingly β(1→4)-linked d-glucose (Glc) and N-acetyl-d-glucosamine (GlcNAc) was synthesized via two modes of enzymatic polymerization. First, a sugar oxazoline monomer of Glcβ(1→4)GlcNAc (1) was designed as a transition-state analogue substrate (TSAS) monomer for chitinase catalysis. Monomer 1 was recognized by chitinase from Bacillus sp., giving rise to a cellulose−chitin hybrid polysaccharide (2) via ring-opening polyaddition with perfect regioselectivity and stereochemistry. Molecular weight (M_n) of 2 reached 4030, which corresponds to 22 saccharide units. Second, a sugar fluoride monomer of GlcNAcβ(1→4)Glc (3) was synthesized for the catalysis of cellulase from Trichoderma viride. The enzyme catalyzed polycondensation of 3, providing a cellulose−chitin hybrid polysaccharide (4) in regio- and stereoselective manner. M_n of 4 reached 2840, which corresponds to 16 saccharide units. X-ray diffraction measurements revealed that these hybrid polysaccharides did not form any characteristic crystalline structures. Furthermore, these unnatural hybrids of 2 and 4 were successfully digested by lysozyme from human neutrophils.