|TUD Organische Chemie||Immel||Structures||CHIME - Cyclogalactins (Informations)||View or Print (this frame only)|
Molecular Modeling of Saccharides, Part IV.
Cyclodextrins, Cyclomannins, and Cyclogalactins with five and six (1→4)-linked Sugar Units: a Comparative Assessment of their Conformations and Hydrophobicity Potential Profiles.
F. W. Lichtenthaler and S. Immel, Tetrahedron: Asymmetry 1994, 5, 2045-2060.
Molecular Modeling of Saccharides, Part XXII.
Conformations and Lipophilicity Profiles of some Cyclic β(1→3)- and β(1→6)-linked Oligogalactofuranosides.
H. Gohlke, S. Immel, and F. W. Lichtenthaler, Carbohydr. Res. 1999, 321, 96-104.
Abstract / Fulltext PDF
Computer-aided generation of the 3d-geometries and the contact surfaces for various cyclogalactins composed of pyranoid and furanoid galactose units provides a lucid picture on their molecular architecture, most notably their cavity dimensions. The MOLCAD program mediated computation of the molecular lipophilicity patterns (MLPs), projected in color-coded form onto the respective contact surfaces allow for the first time a detailed localization of hydrophobic and hydrophilic domains, which determine to a substantial degree the capabilities of these cyclooligosaccharides for inclusion complex formation.
Furanoid Cyclogalactins: 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.