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Molecular Modeling of Saccharides, Part XVII.

Molecular Geometries of Furanoid β(1→3)- and β(1→6)-linked Cyclogalactins

Holger Gohlke, Stefan Immel, Frieder W. Lichtenthaler, and Guido E. Schmitt

Proceedings of the 9th Internat. Symp. on Cyclodextrins (Ed.: J. J. Torres-Labandeira), Kluwer Acad. Publ., Dordrecht, NL, 1998, 63-68.

The conformational properties of small cyclogalactins composed of β(1→3)- and β(1→6)-linked galactofuranose units, i.e cyclo[D-Galf β(1→3)]n, n = 4, 5 (1 and 2), and cyclo[D-Galf β(1→6)]n, n = 3, 4 (3 and 4), were investigated by means of adapted Monte-Carlo simulations. The flexibility of the macrocyclic backbone favors bend and asymmetrical conformations over round geometries. Visualization of the molecular surfaces of the global energy-minimum structures reveal the disk-type shapes of 1 - 4 without central cavities, but featuring distinct indentations close to the 2/3-O-groups, respectively. Molecular lipophilicity patterns prove these surface dents to be hydrophobic for 1 and 2, whereas 3 and 4 display an inverse situation with a hydrophobic outer core structure.

Additional Graphics: Cyclogalactins

© Copyright PD Dr. S. Immel