NMR spectroscopic structural characterization of a water-soluble β-(1→3, 1→6)-glucan from Aureobasidium pullulans

Hiroyuki Kono; Nobuhiro Kondo; Katsuki Hirabayashi; Makoto Ogata; Kazuhide Totani; Shinya Ikematsu; Mitsumasa Osada

doi:10.1016/j.carbpol.2017.07.018

NMR spectroscopic structural characterization of a water-soluble β-(1→3, 1→6)-glucan from Aureobasidium pullulans

Carbohydr Polym. 2017 Oct 15:174:876-886. doi: 10.1016/j.carbpol.2017.07.018. Epub 2017 Jul 10.

Authors

Hiroyuki Kono¹, Nobuhiro Kondo², Katsuki Hirabayashi², Makoto Ogata³, Kazuhide Totani⁴, Shinya Ikematsu⁵, Mitsumasa Osada⁶

Affiliations

¹ Division of Applied Chemistry and Biochemistry, National Institute of Technology, Tomakomai College, Nishikioka 443, Tomakomai, Hokkaido, 059 1275, Japan. Electronic address: kono@tomakomai-ct.ac.jp.
² Itochu Sugar Co. Ltd., Tamatsuura 3, Hekinan, Aichi 447 8506, Japan.
³ Department of Chemistry and Biochemistry, National Institute of Technology, Fukushima College, Nagao 30, Iwaki, Fukushima, 970 8034, Japan.
⁴ Division of Chemical Engineering and Biotechnology, Department of Engineering for Future Innovation, National Institute of Technology, Ichinoseki College, Takanashi, Hagisho, Ichinoseki, Iwate 021 8511, Japan.
⁵ Department of Bioresources Engineering, National Institute of Technology, Okinawa College, Henoko 905, Nago, Okinawa, 905 2192, Japan.
⁶ Department of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386 8567, Japan.

PMID: 28821143
DOI: 10.1016/j.carbpol.2017.07.018

Abstract

An unambiguous structural characterization of the water-soluble Aureobasidium pullulans β-(1→3, 1→6)-glucan is yet to be achieved, although this β-(1→3, 1→6)-glucan is expected to exhibit excellent biofunctional properties. Thus, we herein report the elucidation of the primary structure of the A. pullulans β-(1→3, 1→6)-glucan using nuclear magnetic resonance spectroscopy, followed by comparison of the obtained structure with that of schizophyllan (SPG). Structural characterization of the A. pullulans β-(1→3, 1→6)-glucan revealed that the structural units are a β-(1→3)-d-glucan backbone with four β-(1→6)-d-glucosyl side branching units every six residues. In addition, circular dichroism spectroscopic analysis revealed that the β-(1→3, 1→6)-glucan interacted with polyadenylic acid (poly(A)) chains in DMSO solution to form a complex similar to that obtained in the complexation of SPG/poly(A). This finding indicates that β-(1→3, 1→6)-glucan forms a triple-helical conformation in aqueous solution but exhibits a random coil structure in DMSO solution, which is similar to the behavior of SPG.

Keywords: Aureobasidium pullulans; NMR; Polysaccharide-polynucleotide complex; Schizophyllan; β-(1→3, 1→6)-Glucann.

MeSH terms

Ascomycota / chemistry*
Glucans / chemistry*
Magnetic Resonance Spectroscopy
Water

Substances

Glucans
epiglucan
Water