An orthorhombic crystal form of cyclohexaicosaose, CA26·32.59 H2O: comparison with the triclinic form

Nimz, Olaf; Geßler, Katrin; Usón, Isabel

doi:10.1016/s0008-6215(01)00249-x

Cited by 37 publications

(37 citation statements)

References 21 publications

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“…Physicochemical properties of native CDs and LR-CDs. The crystal structures of 4 kinds of LR-CDs, CD9 (8), CD10 (28-32), CD14 (30,31,33) and CD26 (34,35), have already been described using X-ray crystallographic analysis. It is well known that the molecular structures of α-, β-and γ-CD are a truncated cone with a round cavity as shown in Fig.…”

Section: B Physicochemical Properties and Molecular Structures Of Lr-cdmentioning

confidence: 99%

Large-ring Cyclodextrins

Endō¹

2011

TIGG

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Cyclodextrin (CD) is the common name for cyclic α-1,4-glucans; α-, β-and γ-CD, which are composed of 6, 7, 8 D-glucopyranose units, are well-known. However, most scientists have not recognized large-ring cyclodextrins (LRCDs) composed of more than 9 D-glucopyranose units until recently, although the existence of LR-CDs containing 9-13 D-glucopyranose units in macrocycle was reported about a half century ago. The characteristics of LR-CDs have been studied for the last quarter century, and they are still relatively new materials. In this minireview, the unique characteristics of LR-CDs, including molecular structure, physicochemical properties and inclusion complex formation ability, are discussed. Preparation and purification methods are also reviewed.

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Section: B Physicochemical Properties and Molecular Structures Of Lr-cdmentioning

confidence: 99%

Large-ring Cyclodextrins

Endō¹

2011

TIGG

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“…19,20 Two of the loops give an open shape of the macromolecule, whereas the third loop is significantly closed. The same deformations of CD27 took place during the first nanoseconds of the simulation: becoming more compact and with three tight loops, the macromolecule twisted in the form of a triple propeller.…”

Section: Structural Variations Of the Large-ring Cyclodextrins In Solmentioning

confidence: 99%

“…8,[12][13][14] LR-CDs were first prepared by French et al 15 and the crystal structure determinations of the CDs composed by 9, 16 10, 13,17,18 14,13,17 and 26 19,20 glucose units provided invaluable information on the conformations of these molecules in the crystal lattice. 21 New structural motifs were detected.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics study of the conformational dynamics and energetics of some large‐ring cyclodextrins (CDn, n = 24, 25, 26, 27, 28, 29)

2007

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Molecular dynamics simulations in water solution were performed on six large-ring cyclodextrins (LR-CDs) with a degree of polymerization 24, 25, 26, 27, 28, and 29. The AMBER parm99 force field and explicit water molecules (TIP3P) were used in the simulations. The present research was aimed at further extending our knowledge on the structural dynamics and the energetics of this new class of compounds that may eventually provide chiral cavities suitable for formation of inclusion complexes with small molecules, and, accordingly, to serve as host structures for chiral recognition. The study focused on several representatives flanking CD26-the largest LR-CD for which X-ray data is available. Both the monitoring of the structural variations during the simulations as well as the analyses of energy balances are indicative for high flexibility of the macrorings. Slight differences of the overall preferred shapes were detected with diminishing the size of the macromolecules from CD29 to CD24. An elongated cavity (CD28) or a double parallel strand in different specific representations are the dominating motifs in the LR-CDs studied: with loops at the two ends (CD25, CD28, CD29), with a loop at one end (CD25), twisted (CD26, CD27) or twisted with an open portion in the middle (CD24), helical (CD24, CD25), or linking two loops from one of their sides (CD27). Two loops connected by an arc (CD28, CD29) and a cavity with the shape of an extended rectangular (CD24, CD28) appear preferentially during the conformational interconversions of the two larger CDs, whereas helical motifs are present in the smaller macrorings: an extended helix with ends linked by an arc (CD24), helical turn and helical portion (CD26, CD27). A triple propeller conformation or three symmetrical loops of almost equal size were also detected for CD26 and CD29, respectively. The present results further support the hypothesis for the existence of more than one cavity in large-ring cyclodextrins and suggest preferred conformations in water solution for the LR-CDs with degree of polymerization from 24 to 29.

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“…Advances were marked recently in the study of their physicochemical properties, [5][6][7][8][9][10][11][12][13][14] despite existing difficulties in their synthesis, isolation and purification. Crystal structure determinations were so far successful only for the CDs of size 9, 15 10, 13,16,17 14, 13,16 and 26 18,19 glucose units. 20 New structural motifs were detected and it became evident that their geometries differ considerably from the native CDs (i.e., those composed of 6 (a-CD), 7 (b-CD), and 8 (g-CD) glucose units).…”

Section: Introductionmentioning

confidence: 99%

“…We concluded from examination of snapshots of structures extracted from the trajectory files 59 that conformation of CD26 exists in aqueous solution which is an appropriate starting structure for crystallization to produce the X-ray geometry of two antiparallel left-handed single helices with two stretches that connect the short helices from the upper and from the lower sides. 18,19 In most of the cases, a flip was present in one of the bridging portions, and a kink at the other.All structures examined here present resemblance with the circularized three-turn single helical structure proposed for CD21 from small-angle X-ray scattering 38 or with the representative conformations of the LR-CDs from the closer vicinity of CD26 (Fig. 4 and Supporting Information Fig.…”

mentioning

confidence: 98%

Computational studies on the conformations of some large‐ring cyclodextrins (CDn, n = 20, 21, 22, 23)

Ivanov

2011

Chirality

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Computational studies were carried out on the conformations of large-ring cyclodextrins with degree of polymerization from 20 to 23. Principal component analysis (PCA) was applied for postprocessing of trajectories from conformational search, based on 100.0 ns molecular dynamics simulations. The dominant PCA modes for concerted motions of the macroring atoms were monitored in a lower-dimensions subspace. The first six lowest indexed principal components contribute more than 90% of the total atomic motions in all cases, with about 70% (CD21) to 83% (CD22) contribution coming from the three highest-eigenvalue principal components. Representative average geometries of the cyclodextrin macrorings were also obtained for the whole simulation and for the ten 10.0 ns time intervals of the simulation. We concluded that resemblance exists of the representative conformations of these four cyclodextrins with the circularized three-turn single helical structure proposed for CD21 from small-angle X-ray scattering, as well as with the representative conformations of CD26.

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An orthorhombic crystal form of cyclohexaicosaose, CA26·32.59 H2O: comparison with the triclinic form

Cited by 37 publications

References 21 publications

Large-ring Cyclodextrins

Large-ring Cyclodextrins

Molecular dynamics study of the conformational dynamics and energetics of some large‐ring cyclodextrins (CDn, n = 24, 25, 26, 27, 28, 29)

Computational studies on the conformations of some large‐ring cyclodextrins (CDn, n = 20, 21, 22, 23)

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