Anomeric and Exo-Anomeric Effects in Carbohydrate Chemistry

Tvaroŝka, Igor; Bleha, Tomáš

doi:10.1016/s0065-2318(08)60412-6

Cited by 337 publications

(168 citation statements)

References 175 publications

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“…[30][31][32] Indeed, in A-amylose, there is a number of hydrogen bonds between adjacent double helices whereas in B-amylose, the connections between the double helices are mainly through hydrate water bridges. [28][29][30] The crystal cohesion and therefore the thermal susceptibility of both allomorphs is thus expected to be substantially different. This is indeed the case since A-amylose crystals systematically melt by about 20°C above the B-specimens when subjected to the same hydrothermal treatment.…”

Section: Discussionmentioning

confidence: 99%

Crystal Structure of A-amylose: A Revisit from Synchrotron Microdiffraction Analysis of Single Crystals

et al. 2009

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The three-dimensional structure of A-amylose crystals, as a model of the crystal domains of A-starch granules, was revised using synchrotron radiation microdiffraction data collected from individual micron-sized single crystals. The resulting datasets allowed a determination of the structure with conventional X-ray structure determination techniques normally used for small molecules and not for polymers. Whereas the gross features of this improved structure do not differ extensively from previous structure determination, the high resolution of the diffraction diagrams, which is unusual for a crystalline polymer, allowed the resolution of important new fine details. These include a distortion of the amylose double helices resulting from the occurrence of two intracrystalline molecules of water and a tight network of hydrogen bonds involving each of the primary and secondary hydroxyl groups of the glucosyl moieties. Pairs of water molecules are located in discrete pockets that do not interfere with one another. In addition, the refinement of the new structure indicates a "parallel-down" organization of the amylose molecules within the unit cell as opposed to the previous "parallel-up" model. This new feature indicates that within the crystals, the nonreducing ends of the amylose molecules are oriented toward the c-axis direction of the unit cell. The description of this geometry is important to correlate the crystallography of the granules of A-starch with their ultrastructure and their mode of biosynthesis.Here, we present for the first time the resolution of the structure of a polymer crystal from a full X-ray dataset collected on micron-sized polymer single crystals using synchrotron radiation microdiffraction. This achievement is a substantial advance, which opens the way to many more studies since the technique of growing polymer and biopolymer single crystals is well established.3

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Section: Discussionmentioning

confidence: 99%

Crystal Structure of A-amylose: A Revisit from Synchrotron Microdiffraction Analysis of Single Crystals

et al. 2009

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“…It is also known thatxylopyranosyl fluoride triacetate is present mainly in the 1 C 4 conformation, even though that conformation has the unfavorable 1,3-diaxial interaction of bulky ester group. 47,48) Our NMR analysis of the -xylopyranosyl fluoride triacetate also revealed that it should be of the 1 C 4 conformation, because it shows 4.1 Hz of the vicinal H 1 -H 2 coupling (unpublished data). Accordingly, -xylopyranosyl fluoride, of which the 1,3-diaxial repulsion of hydroxy group must be much weaker than the bulky acetyl group, can exit in the 1 C 4 conformation.…”

Section: )mentioning

confidence: 85%

Function and Structure Studies of GH Family 31 and 97 α-Glycosidases

Okuyama

2011

Bioscience, Biotechnology, and Biochemistry

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“…As expected, the α/β anomer ratios of glucose were very different depending on the solvent, with α/β anomer ratios of 44.4:55.6 in DMAC-d 9 and of 83.3:16.7 in THF-d 8 (Supplementary Figure S3). Although these data clearly showed that anomeric composition of glucose solutions subjected to the acrylation step was very different depending on the solvent, they could not be used to decipher α/β anomer ratios of each Glu-nA reaction product for a variety of reasons, amongst which were potential anomeric effect during glucose acrylation (as often observed for substituted sugars [36]), suppression effects during ESI of such raw samples, or differential ionization yield of each species.…”

Section: Cid Of [Glu-na + Nh 4 ]mentioning

confidence: 92%

Anomerization of Acrylated Glucose During Traveling Wave Ion Mobility Spectrometry

Chendo

Moreira

Tintaru

et al. 2015

J. Am. Soc. Mass Spectrom.

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Abstract. Anomerization of simple sugars in the liquid phase is known as an acidand base-catalyzed process, which highly depends on solvent polarity. This reaction is reported here to occur in the gas phase, during traveling wave ion mobility spectrometry (TWIMS) experiments aimed at separating α-and β-anomers of penta-acrylated glucose generated as ammonium adducts in electrospray ionization. This compound was available in two samples prepared from glucose dissolved in solvents of different polarity, namely tetrahydrofuran (THF) and N,Ndimethylacetamide (DMAC), and analyzed by electrospray tandem mass spectrometry (ESI-MS/MS) as well as traveling wave ion mobility (ESI-TWIMS-MS). In MS/MS, an anchimerically-assisted process was found to be unique to the electrosprayed α-anomer, and was only observed for the THF sample. In ESI-TWIMS-MS, a signal was measured at the drift time expected for the α-anomer for both the THF and DMAC samples, in apparent contradiction to the MS/MS results, which indicated that the α-anomer was not present in the DMAC sample. However, MS/MS experiments performed after TWIMS separation revealed that ammonium adducts of the α-anomer produced from each sample, although exhibiting the same collision cross section, were clearly different. Indeed, while the α-anomer actually present in the THF sample was electrosprayed with the ammonium adducted at the C2 acrylate, its homologue only observed when the DMAC sample was subjected to TWIMS hold the adducted ammonium at the C1 acrylate. These findings were explained by a β/α inter-conversion upon injection in the TWIMS cell, as supported by theoretical calculation and dynamic molecular modeling.

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Anomeric and Exo-Anomeric Effects in Carbohydrate Chemistry

Cited by 337 publications

References 175 publications

Crystal Structure of A-amylose: A Revisit from Synchrotron Microdiffraction Analysis of Single Crystals

Crystal Structure of A-amylose: A Revisit from Synchrotron Microdiffraction Analysis of Single Crystals

Function and Structure Studies of GH Family 31 and 97 α-Glycosidases

Anomerization of Acrylated Glucose During Traveling Wave Ion Mobility Spectrometry

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