Dimeric β-cyclodextrin complexes may mimic membrane diffusion transport

Stezowski, John J.; Jogun, Kurt H.; Eckle, Emil; Bartels, Klaus

doi:10.1038/274617a0

Cited by 81 publications

(34 citation statements)

References 4 publications

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“…3. This dimer structure is similar to that found for the other dimeric fl-CD complexes (Hamilton, Sabesan, Steinrauf & Geddes, 1976;Stezowski, Jogun, Eckle & Bartels, 1978;Harding, Maclennan & Paton, 1978) but, as shown in Fig. 4, the dimers stack along the b axis to produce a new type of packing, 'bent structure'.…”

Section: Introductionsupporting

confidence: 54%

Structure of the β-cyclodextrin (β-CD) inclusion complex with p-ethylaniline (PEA)

Tokuoka¹,

Fujiwara²,

Tomita³

1981

Acta Crystallogr Sect B

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Section: Introductionsupporting

confidence: 54%

Structure of the β-cyclodextrin (β-CD) inclusion complex with p-ethylaniline (PEA)

Tokuoka¹,

Fujiwara²,

Tomita³

1981

Acta Crystallogr Sect B

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“…Initial phases were derived from isomorphous replacement of the ␤-CD coordinates from the thermodynamically stable npropanol complex (22,23). Waters of hydration and guest sites were located in difference electron density.…”

Section: Methodsmentioning

confidence: 99%

“…All diffraction measurements were conducted with graphite monochromated Ag K ␣ X-radiation ( ϭ 0.5608 Å) by using a Bruker AXS (Madison, WI) rotating anode x-ray source; data were measured in oscillation scan mode with a MARResearch (Hamburg, Germany) (18 cm) imaging plate area detector and processed by using the MARXDS program (21). Data collection and structure refinement are characterized in Table 1.Initial phases were derived from isomorphous replacement of the ␤-CD coordinates from the thermodynamically stable npropanol complex (22,23). Waters of hydration and guest sites were located in difference electron density.…”

mentioning

confidence: 99%

Chiral discrimination in cyclodextrin complexes of amino acid derivatives: β-cyclodextrin/ N -acetyl- l -phenylalanine and N -acetyl- d -phenylalanine complexes

Alexander

Clark

Brett

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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In a systematic study of molecular recognition of amino acid derivatives in solid-state ␤-cyclodextrin (␤-CD) complexes, we have determined crystal structures for complexes of ␤-cyclodextrin͞N-acetyl-L-phenylalanine at 298 and 20 K and for N-acetyl-D-phenylalanine at 298 K. The crystal structures for the N-acetyl-L-phenylalanine complex present disordered inclusion complexes for which the distribution of guest molecules at room temperature is not resolvable; however, they can be located with considerable confidence at low temperature. In contrast, the complex with N-acetyl-D-phenylalanine is well ordered at room temperature. The latter complex presents an example of a complex in this series in which a water molecule is included deeply in the hydrophobic torus of the extended dimer host. In an effort to understand the mechanisms of molecular recognition giving rise to the dramatic differences in crystallographic order in these crystal structures, we have examined the intermolecular interactions in detail and have examined insertion of the enantiomer of the D-complex into the chiral ␤-CD complex crystal lattice.C hiral cyclodextrin (CD) hosts have been used extensively as models for investigating chiral and molecular recognition. Solution studies of CD inclusion complexes (1-3) and determination of binding constants (2), have provided thermodynamic data useful for chromatographic applications (4-8). In the solid phase, x-ray diffraction studies of inclusion complexes with chiral guest molecules can provide direct information regarding the mechanism of chiral recognition. In the relatively few studies with native cyclodextrins, mixed results have been reported (9-15). The most complete studies are those in which structures are determined for complexes formed with both enantiomers separately and for the racemate (9-14). For example, significant discrimination was observed for the ␤-CD inclusion complex with (R,S)-fenoprofen (11) in the solid state, whereas there was no apparent discrimination for (R,S)-flurbiprofen (9-14). These results and others suggest that features such as guest fit to the cavity, solvent interactions, hydrogen bonding potential of the guest molecules, and host crystal packing arrangement combine to play a significant role in chiral discrimination.We have initiated a study in which the crystal lattice of ␤-cyclodextrin complexes that crystallize in the intermediate (Im) packing motif (16-18) has been characterized as a binding pocket useful for the crystallographic study of structural aspects of molecular recognition at high resolution (19). Briefly, the crystal lattice consists of close packed hydrogen bonded dimers of the host ␤-cyclodextrin molecules stacked, with an intervening layer of water molecules, along the a-axis. Typically two amino acid derivative guest molecules are included in the extended torus of the host dimer. To differing extents, the more hydrophilic backbones of the guest molecules interact with water molecules between the sheets and, in most cases, via bridging water molec...

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“…About 100 calorimetric investigations involving macrocyclic compounds have been reported, most of them on cyclodextrins, see for example [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. For recent work on crown ethers, see [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…The requested values of the thermodynamic quantities at different temperatures have been obtained by isothermal titration calorimetry. This technique yields the binding constant, K, and the enthalpy change, ∆H°, from which the free energy change, ∆G°, the entropy change, ∆S°, and the change in heat capacity upon binding, ∆C p°, are obtained [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Isoperibolic Titration Calorimetry as a Tool for the Prediction of Thermodynamic Properties of Cyclodextrins

Moreno–Piraján

Giraldo

2008

Energies

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Abstract:The interaction of guest molecules ranging from pentan-1-ol to octan-1-ol with α-cyclodextrin (α-CD) in water of has been studied calorimetrically at 283.15, 288.15, 293.15, 298.15 and 308.15 K with an isoperibolic titration calorimeter designed in our laboratory. The calorimetric method employed allows the determination of the thermodynamic parameters characterizing the binding process, ∆G°m, ∆H°m, ∆S°m and ∆Cp°, namely free energy, enthalpy, and calorific capacity. These results show that in the temperature range investigated, the entropy change increased with chain length. This is in line with what is expected for a hydrophobic dehydration process. However, that effect is not expected to lead to the more pronounced negative CH 2 -increment observed for n c > 5 or 6. As for many other ligand binding processes, we can observe a significant enthalpyentropy compensation for this system, both with respect to temperature and structure.

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Dimeric β-cyclodextrin complexes may mimic membrane diffusion transport

Cited by 81 publications

References 4 publications

Structure of the β-cyclodextrin (β-CD) inclusion complex with p-ethylaniline (PEA)

Structure of the β-cyclodextrin (β-CD) inclusion complex with p-ethylaniline (PEA)

Chiral discrimination in cyclodextrin complexes of amino acid derivatives: β-cyclodextrin/ N -acetyl- l -phenylalanine and N -acetyl- d -phenylalanine complexes

Isoperibolic Titration Calorimetry as a Tool for the Prediction of Thermodynamic Properties of Cyclodextrins

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