Investigation of the conformational behaviour of permethylated cyclodextrins by molecular modelling

Reinhardt, Robert M.; Richter, Maik; Mager, Peter P.

doi:10.1016/s0008-6215(96)00151-6

Cited by 21 publications

(13 citation statements)

References 26 publications

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“…49 Therefore, discrepancy between our results and those of Reale et al could be partially justified by taking into account the hydrated radii (r h ) rather than crystal ionic radii (r i ). 68 Similar trends were observed by X-ray analysis where permethylated cyclodextrins are remarkably distorted from the regular polygonal structure. When the cone voltage increases, the desolvation process is faster and leads to disruption of the hydration sphere (water molecules are removed), strengthening the electrostatic interaction between b-CD and the cation.…”

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confidence: 66%

“…56,67 The case of lithium is quite particular, since it is emphasized that identification of the binding or coordination sites between CDs and this small cation by ESI-MS is still a challenge. 68 Hydrogen bridges between primary hydroxyl groups of adjacent glucose units (not observed in TRIMEB) led to stabilization of the native host molecule conformations (low standard deviations of the calculated values), whereas the permethylated non-stabilized structures are more flexible (standard deviations are larger) enlarging the diameters by 3, 3.5 and 7.8% for glycosidic, primary and secondary oxygens, respectively, between b-CD and TRIMEB. Indeed, the hydrated cations exhibit larger radii equal to 331 pm (E+2.5 fold), 358 pm (E+3.6 fold), 382 pm (E+6.0 fold), 329 pm (E+2.1 fold) and 329 pm (E+2.0 fold), for K + , Na + , Li + , Rb + and Cs + , respectively.…”

Section: View Article Onlinementioning

confidence: 97%

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Probing the common alkali metal affinity of native and variously methylated β-cyclodextrins by combining electrospray-tandem mass spectrometry and molecular modeling

Przybylski

Bonnet

Cézard

2015

Phys. Chem. Chem. Phys.

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In the study herein, we investigated the solution and gas phase affinity of native and variously methylated β-cyclodextrins (CDs) as hosts towards three common alkali metals as guests namely lithium, sodium and potassium. For this purpose, two complementary approaches have been employed: electrospray-tandem mass spectrometry (ESI-MS/MS) with two energetic regimes: Collision Induced Dissociation (CID) and Higher Collision Dissociation (HCD), respectively, and DFT molecular modeling. These approaches have been achieved by taking into account the interaction of either one or two alkali metals with the host molecules. The results showed a good agreement between experimental and theoretical data. It was demonstrated that increasing the methylation degree strengthened the gas phase affinity towards all studied alkali metals. Furthermore, it was established that the cation selectivity was Na(+) > Li(+) > K(+) and Li(+) > Na(+) > K(+) for the solution and gas phase, respectively.

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Section: View Article Onlinesupporting

confidence: 66%

Section: View Article Onlinementioning

confidence: 97%

Probing the common alkali metal affinity of native and variously methylated β-cyclodextrins by combining electrospray-tandem mass spectrometry and molecular modeling

Przybylski

Bonnet

Cézard

2015

Phys. Chem. Chem. Phys.

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“…[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Some of these studies have aided the interpretation of nuclear magnetic resonance (NMR) and other experimental techniques in the context of CD complexes. [23][24][25][26][27][28] However, conformational analyses of energetically stable conformations of the CDs [12][13][14] and their complexes [15][16][17][18][19][20][21][22] have been the main targeted subjects. Molecular dynamics (MD) simulations are more timeconsuming but provide a better connection between atomistic constitution and macroscopic properties when compared to pure geometry optimizations methods.…”

Section: Introductionmentioning

confidence: 99%

Revisiting the internal conformational dynamics and solvation properties of cyclodextrins

Pereira¹,

Moura²,

Freitas³

et al. 2007

J. Braz. Chem. Soc.

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Simulações de dinâmica molecular são utilizadas para investigar a dinâmica conformacional interna e propriedades de solvatação das três ciclodextrinas naturais, α-, β-e γ-ciclodextrina em água e temperatura ambiente. Estes oligossacarídeos derivados da glicose apresentam uma estrutura molecular peculiar que lhes confere a habilidade de formar complexos de inclusão e modificar as propriedades físico-químicas das moléculas complexadas. As características estruturais das ciclodextrinas em solução são determinantes para a complexação. As análises das trajetórias obtidas mostram que ligações de hidrogênio secundárias entre resíduos de glicose adjacentes estão presentes em solução e apresentam um caráter altamente dinâmico, onde ligações de hidrogênio alternativas podem ser formadas com moléculas de água. Apesar do baixo caráter hidrofílico, as cavidades apresentam-se solvatadas e o número de moléculas de água dentro da cavidade é aproximadamente duplicada por unidade de glicose adicionada ao macrociclo. Os tempos de residência para as moléculas de água dentro das cavidades são inversamente proporcionais ao seu respectivo tamanho.Molecular dynamics simulations were used to investigate the internal conformational dynamics and solvation properties of the three natural cyclodextrins, α-, β-and γ-cyclodextrin in aqueous solution at room temperature. These glucose-derived oligosacharides present a molecular structure that confers them the ability to complex guest molecules and change their physicochemical properties. The structural behavior of cyclodextrins in solution is crucial for their complexation abilities. Analyses of the obtained trajectories show that inter-glucose hydrogen bonds between the secondary hydroxyl groups are present in solution, but show a very dynamical character where alternative hydrogen bonds to water molecules can be formed. Despite the lower hydrophilicity of the cyclodextrins inner-cavities, they were found to be solvated and the number of water molecules inside the cavity roughly doubles per glucose unit added to the ring. The residence times for water molecules inside the cavities are inversely proportional to the cavity size. Keywords: cyclodextrins, molecular dynamics, solvation, flexibility IntroductionCyclodextrins (CDs) have been extensively studied since their discovery in the late nineteenth century.1 Their peculiar properties and behavior have interested scientists in many different fields.2 These cyclic oligosaccharides, obtained from starch by glucanotransferase degradation, are formed by a certain number of α-D-glucopyranose units linked by α(1→4) glycosidic bonds. This arrangement produces a truncated cone shape with a central cavity relatively hydrophobic and an external surface relatively hydrophilic.1-3 Naturally occurring CDs, known as α-, β-and γ-CD, present six, seven and eight glucose units, respectively.1-3 The structural features of these saccharides allow them to form inclusion complexes with a great variety of compounds.3 Due to their ability to form host-guest complexe...

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“…Concerning the host molecule, the number of glucopyranose units, and the diameter of the cavity (26), the nature of the chemical groups (hydroxyl and methoxy groups) at the edges of the cavity (27,35), the polarity of each cyclic unit molecule, and the distribution of the charges, etc., are relevant factors in understanding the ability of CD to form water-soluble guest-CD inclusion complexes (27). On the other hand, the chemical properties of the guest molecules, such as the global charges of lipid molecules, the electrostatic properties of the lipid headgroups, and the nature of the acyl chains of the lipids (length and degree of unsaturation), are also determinative for generating this engulfing process (24).…”

Section: Discussionmentioning

confidence: 99%

“…First, let us consider the host characteristics: It has been reported that the permethylation of CD enlarges the whole cavity of the molecule (35). The methyl groups introduced into the O 3 position extend the O 2 -O 3 side of the cavity and make narrower the O 6 side (27), thus favoring the formation of inclusion complexes.…”

Section: Discussionmentioning

confidence: 99%

Cyclodextrins: A potential tool for studying the role of glycerolipids in photosynthetic membranes

Duchêne¹,

Siegenthaler²

2002

Lipids

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A novel cyclodextrin derivative, i.e., permethylated-alpha-cyclodextrin (PM-alpha-CD), was used for removing glycerolipids from spinach thylakoid membranes and investigating their role in photosynthetic activities. A three-step selective removal of each lipid class was observed in treated membranes. Up to a concentration of 4 mM, PM-alpha-CD (in the presence of 75 microg chlorophyll a+b/mL), PM-alpha-CD displayed a marked selectivity for anionic lipids [sulfoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG)] in comparison with galactolipids. At this concentration, half of PG and SQDG were removed. Within this range of concentration, the volume response of treated thylakoids to variation of osmolarity, an indirect mean of verifying the structural integrity of the membrane, was not altered. Similarly, neither photosystem II (PSII) nor photosystem I (PSI) activity was affected. In contrast, the low-temperature fluorescence ratio F695/F740 drastically diminished from 1.45 to about 0.7, essentially due to the decrease of PSII fluorescence. The results derived from the fast fluorescence rise expressed in the form of a spider suggest that the fraction of inactivated (non-Q(A) reducing) reaction centers (RC) increases while the active (Q(A) reducing) RC remained intact. Raising the concentration of PM-alpha-CD from 4 to 7 mM resulted in a progressive but greater diminution of the galactolipid level than that of SQDG and PG. Within this concentration range, the integrity of the membrane was not altered, nor was either PSII or PSI activity, whereas the F695/F740 ratio decreased to about 0.45 as well as the fraction of inactivated RC. At concentrations above 7 mM of PM-alpha-CD, the integrity of the membrane was impaired, resulting in a decrease of both electron transport activities. At all concentrations, PM-alpha-CD did not show any selectivity toward either the acyl chains of the lipid molecules or the molecular species of PG. The results are discussed in terms of the role of glycerolipids in thylakoid membrane function and the relationship of the chemical structure of PM-alpha-CD and its lipid removal capacity.

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Investigation of the conformational behaviour of permethylated cyclodextrins by molecular modelling

Cited by 21 publications

References 26 publications

Probing the common alkali metal affinity of native and variously methylated β-cyclodextrins by combining electrospray-tandem mass spectrometry and molecular modeling

Probing the common alkali metal affinity of native and variously methylated β-cyclodextrins by combining electrospray-tandem mass spectrometry and molecular modeling

Revisiting the internal conformational dynamics and solvation properties of cyclodextrins

Cyclodextrins: A potential tool for studying the role of glycerolipids in photosynthetic membranes

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