TUD Organische ChemieImmelStructuresCHIME - Cyclogalactins (Informations)View or Print this frame onlyView or Print (this frame only)

Cyclogalactins (CGs)

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[1] 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.

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  1. SYBYL-MOLCAD module: (a) J. Brickmann, MOLCAD - MOLecular Computer Aided Design, Technical University of Darmstadt, 1992. The major part of the MOLCAD program is included in the MOLCAD-module of the SYBIL package of TRIPOS Associates, St. Louis, USA. - (b) J. Brickmann and M. Waldherr-Teschner, Labo (Hoppenstedt Verlag, Darmstadt) 1989, 10, 7-14; Informationstechnik (Oldenburg Verlag, München) 1991, 33, 83-90. - (c) J. Brickmann, J. Chim. Phys. 1992, 89, 1709-1721. - (d) M. Waldherr-Teschner, T. Goetze, W. Heiden, M. Knoblauch, H. Vollhardt, and J. Brickmann, in: Advances in Scientific Visualization (Eds.: F. H. Post, A. J. S. Hin), Springer Verlag, Heidelberg, 1992, pp. 58-67. - (e) J. Brickmann, T. Goetze, W. Heiden, G. Moeckel, S. Reiling, H. Vollhardt, and C.-D. Zachmann, Interactive Visualization of Molecular Scenarios with MOLCAD/SYBIL, in: Data Visualization in Molecular Science - Tools for Insight and Innovation (Ed.: J. E. Bowie), Addison-Wesley Publishing Company Inc., Reading, Mass., 1995, pp. 83-97.

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