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An Improvement in the Bending Ability of a Hinged Trisaccharide with the Assistance of a Sugar––Sugar Interaction
Author(s) -
Yuasa Hideya,
Izumi Takuhiro,
Mitsuhashi Nobuyuki,
Kajihara Yasuhiro,
Hashimoto Hironobu
Publication year - 2005
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200500096
Subject(s) - chemistry , trisaccharide , bent molecular geometry , chelation , stereochemistry , bending , population , disaccharide , metal , crystallography , organic chemistry , materials science , composite material , demography , sociology
Hinged di‐ and trisaccharides incorporating 2,4‐diamino‐β‐ D ‐xylopyranoside as a hinge unit (Hin) were synthesized. Bridging of the diamino group of Hin by carbonylation or chelation to a metal ion results in a conformational change from 4 C 1 to 1 C 4 , which in turn causes a bending of the oligosaccharides. In this study, the bending abilities of the hinged oligosaccharides were compared, in terms of the reactivities toward carbonylation and chelation. Di‐ or trisaccharides containing a 6‐ O ‐glycosylated mannopyranoside or galactopyranoside at their reducing ends had bending abilities similar to that of the Hin monosaccharide, probably because there were neither attractive nor repulsive interactions between the reducing and nonreducing ends. However, when Hin was attached at O2 of methyl mannopyranoside (ManαMe), the bending ability was dependent on the nonreducing sugar and the reaction conditions. Typically, a disaccharide—Hinβ(1,2)ManαMe—was difficult to bend under all the tested reaction conditions, and the bent population in the presence of Zn II was only 4 %. On the other hand, a trisaccharide—Manα(1,3)Hinβ(1,2)ManαMe—was bent immediately after the addition of Zn II or Hg II , and the bent population reached 75 %, much larger than those of all the other hinged trisaccharides ever tested (<40 %). This excellent bending ability suggests an attractive interaction between the reducing and nonreducing ends. The extended conformation was recovered by the addition of triethylenetetramine, a metal ion chelator. Reversible, quick, and efficient bending of the hinged trisaccharide was thus achieved.