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Neutron Diffraction Analysis of γ-Cyclodextrin: A Hydrogen-Bond Study

  • B. E. Hingerty
  • G. L. Hardgrove
  • W. Saenger
Chapter
Part of the Basic Life Sciences book series (BLSC, volume 27)

Abstract

As part of a long-term project on the nature of the hydrogen bond, we have studied various cyclodextrin complexes. Cyclodex-trins have been studied as model enzyme systems (W. Saenger et al., Bioorg. Chem. 5:187–95, 1976). The hydrogen-bonding systems of both α-cyclodextrin (α-CD; cyclohexaamylose) (B. Klar et al., Acta Crystallogr. B36:1154–65, 1980) and β-cyclodextrin (β-CD; cycloheptaamylose) (W. Saenger et al., Nature 296:581–3, 1982) have been studied by neutron diffraction. The α-CD hydrate structure is crystallized with a well-ordered H-bond network displaying circles of hydrogen bonds. (W. Saenger, Nature 278:343–4, 1979). The β-CD hydrate is a partially disordered system, displaying an unusual “flip-flop” cooperative hydrogen-bond network (op. cit.). γ-Cyclodextrin, with a partially disordered system similar to β-CD, is now being studied to see whether “flip-flop” hydrogen bonding also occurs in this case. Coordinates from the x-ray structure of γ-CD·17H2O were supplied by J.M. MacLennan and J.J. Stezowski (Biochem. Biophys. Res. Commun. 92:926–32, 1980). Neutron diffraction data were collected at the Oak Ridge High Flux Isotope Reactor (HFIR). The Chemistry Division’s four-circle diffractometer with a monochromatized wavelength of 1.015 Å. was used for the data collection at room temperature. The crystal used had a space group of P21, with a. 20.287(10) Å, b = 11.079(7) Å, c = 16.858(12) Å, and β = 105.07(4) Å. An experimental absorption correction was applied. Using just the C, O, and H atoms of γ-CD and excluding all water and hydroxyl hydrogens gave an R-factor of 0.244 for 3509 reflections for which I > σ. A number of additional H-atoms have been added, and the current R-factor is 0.121. (Research sponsored by the U.S. Department of Energy, under contract W-7405-ENG-26 with the Union Carbide Corp.)

Keywords

Diffraction Data Neutron Diffraction Federal Republic Absorption Correction Union Carbide 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Copyright information

© Springer Science+Business Media New York 1984

Authors and Affiliations

  • B. E. Hingerty
    • 1
  • G. L. Hardgrove
    • 3
  • W. Saenger
    • 2
  1. 1.Oak Ridge National LaboratoryOak RidgeUSA
  2. 2.Institut für KristallographieFreie Universität BerlinBerlin 33Federal Republic of Germany
  3. 3.Oak Ridge National Lab.USA

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