NMR study of short beta(1-3)-glucans provides insights into the structure and interaction with Dectin-1

作者：Hanashima Shinya; Ikeda Akemi; Tanaka Hiroshi; Adachi Yoshiyuki; Ohno Naohito; Takahashi Takashi; Yamaguchi Yoshiki^*

来源：Glycoconjugate Journal, 2014, 31(3): 199-207.

DOI：10.1007/s10719-013-9510-x

• beta-glucan
• Dectin-1
• DOSY
• STD-NMR
• Isotope shift

beta(1-3)-Glucans, abundant in fungi, have the potential to activate the innate immune response against various pathogens. Although part of the action is exerted through the C-type lectin-like receptor Dectin-1, details of the interaction mechanism with respect to glucan chain-length remain unclear. In this study, we investigated a set of short beta(1-3)-glucans with varying degree of polymerization (DP); 3, 6, 7, 16, and laminarin (average DP; 25), analyzing the relationship between the structure and interaction with the C-type lectin-like domain (CTLD) of Dectin-1. The interaction of short beta(1-3)-glucans (DP6, DP16, and laminarin) with the CTLD of Dectin-1 was systematically analyzed by H-1-NMR titration as well as by saturation transfer difference (STD)-NMR. The domain interacted weakly with DP6, moderately with DP16 and strongly with laminarin, the latter plausibly forming oligomeric protein-laminarin complexes. To obtain structural insights of short beta(1-3)-glucans, the exchange rates of hydroxy protons were analyzed by deuterium induced C-13-NMR isotope shifts. The hydroxy proton at C4 of laminarin has slower exchange with the solvent than those of DP7 and DP16, suggesting that laminarin has a secondary structure. Diffusion ordered spectroscopy revealed that none of the short beta(1-3)-glucans including laminarin forms a double or triple helix in water. Insights into the interaction of the short beta(1-3)-glucans with Dectin-1 CTLD provide a basis to understand the molecular mechanisms of beta-glucan recognition and cellular activation by Dectin-1.

• 出版日期2014-4