The Composition and Conformation of Sugars in Solution

Angyal, S. J.

doi:10.1002/anie.196901571

Cited by 419 publications

(253 citation statements)

References 60 publications

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“…The light polarimetry results presented here provide quantitative data on the extent of the population shift, shown in Figure 7. The observed percent of α-glucose in aqueous solution without salt added is similar to values previously reported by Angyal 21 and by Zhu et al 22 The significant result is the difference in direction of the change in α-glucose population due to the addition of either NaCl or CaCl 2 and the difference in magnitude of the change. As more CaCl 2 is added to the aqueous glucose solution, the population of α-glucose increases.…”

Section: ■ Experimental Methodssupporting

confidence: 89%

“…Both α-and β-glucose isomers are considered because they are in equilibrium in aqueous solution. 21,22,41 The QM studies capture electronic structure of the glucose molecule due to the presence of a sodium ion. Thus, important features such as the oxygen lone pairs are captured, which are considered an important factor in determining energies of stable conformations of glucose.…”

Section: ■ Introductionmentioning

confidence: 99%

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Sodium Ion Interactions with Aqueous Glucose: Insights from Quantum Mechanics, Molecular Dynamics, and Experiment

Mayes

Tian

Nolte³

et al. 2013

J. Phys. Chem. B

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In the last several decades, significant efforts have been conducted to understand the fundamental reactivity of glucose derived from plant biomass in various chemical environments for conversion to renewable fuels and chemicals. For reactions of glucose in water, it is known that inorganic salts naturally present in biomass alter the product distribution in various deconstruction processes. However, the molecular-level interactions of alkali metal ions and glucose are unknown. These interactions are of physiological interest as well, for example, as they relate to cation-glucose cotransport. Here, we employ quantum mechanics (QM) to understand the interaction of a prevalent alkali metal, sodium, with glucose from a structural and thermodynamic perspective. The effect on B-glucose is subtle: a sodium ion perturbs bond lengths and atomic partial charges less than rotating a hydroxymethyl group. In contrast, the presence of a sodium ion significantly perturbs the partial charges of Î±-glucose anomeric and ring oxygens. Molecular dynamics (MD) simulations provide dynamic sampling in explicit water, and both the QM and the MD results show that sodium ions associate at many positions with respect to glucose with reasonably equivalent propensity. This promiscuous binding nature of Na + suggests that computational studies of glucose reactions in the presence of inorganic salts need to ensure thorough sampling of the cation positions, in addition to sampling glucose rotamers. The effect of NaCl on the relative populations of the anomers is experimentally quantified with light polarimetry. These results support the computational findings that Na + interacts similarly with a-and B-glucose. ABSTRACT: In the last several decades, significant efforts have been conducted to understand the fundamental reactivity of glucose derived from plant biomass in various chemical environments for conversion to renewable fuels and chemicals. For reactions of glucose in water, it is known that inorganic salts naturally present in biomass alter the product distribution in various deconstruction processes. However, the molecular-level interactions of alkali metal ions and glucose are unknown. These interactions are of physiological interest as well, for example, as they relate to cation-glucose cotransport. Here, we employ quantum mechanics (QM) to understand the interaction of a prevalent alkali metal, sodium, with glucose from a structural and thermodynamic perspective. The effect on β-glucose is subtle: a sodium ion perturbs bond lengths and atomic partial charges less than rotating a hydroxymethyl group. In contrast, the presence of a sodium ion significantly perturbs the partial charges of α-glucose anomeric and ring oxygens. Molecular dynamics (MD) simulations provide dynamic sampling in explicit water, and both the QM and the MD results show that sodium ions associate at many positions with respect to glucose with reasonably equivalent propensity. This promiscuous binding nature of Na + suggests that computational studies of g...

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Section: ■ Experimental Methodssupporting

confidence: 89%

Section: ■ Introductionmentioning

confidence: 99%

Sodium Ion Interactions with Aqueous Glucose: Insights from Quantum Mechanics, Molecular Dynamics, and Experiment

Mayes

Tian

Nolte³

et al. 2013

J. Phys. Chem. B

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“…32 This phenomenon evidently results from the interaction of the dipoles operating in the C1'-O and C1'-N bonds, which tend to become oriented in the opposite directions. The C1'-N bond in the most stable conformation of N-nucleosides tends to occupy a quasi-axial position, thus moving out of the average plane of the furanose ring.…”

Section: The Anomeric Effect and Deoxyribose Conformationmentioning

confidence: 99%

C-Nucleosides Derived from Simple Aromatic Hydrocarbons

Chaudhuri

Ren

Kool

1997

Synlett

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“…It is very unlikely that this effect is due to a conformational change of the sugar since usually the pyranoid sugar exhibits a high degree of conformational homogeneity in one of the two chair-like conformations [18] needing a large energetic contribution to be changed [19]. It seems likely that the change of the CD signal of the o-nitrophenyl ring is due to asymmetric interactions with vicinal groups of the protein.…”

Section: Resultsmentioning

confidence: 99%

Circular Dichroism Studies of the Binding of o‐Nitrophenyl‐β‐d‐fucoside and o‐Nitrophenyl‐β‐d‐galactoside to Lac Repressor

Maurizot

Charlier

1977

European Journal of Biochemistry

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The binding of o-nitrophenyl-P-D-fucoside and o-nitrophenyl-/?-D-galactoside to Escherichia coli lac repressor was investigated by circular dichroism in the wavelength range 300 -400 nm corresponding to the o-nitrophenyl chromophores. The CD signal of both ligands drastically changed when they bound to lac repressor due to the asymmetric interaction of the o-nitrophenyl ring with chemical groups of protein. The CD spectra of bound ligands indicate close similarity between the environment of o-nitrophenyl-P-D-fucoside and o-nitrophenyl-/?-D-galactoside on lac repressor. The CD signal is used to calculate the binding parameters ( K and n) to lac repressor. It is demonstrated that the limited proteolytic digestion of lac repressor which gives a 'core protein' does not affect the environment of both ligands on the protein.A variety of sugars, natural or synthetic, are able to induce the lac operon in vivo [l]. In contrast, many non-metabolized sugars are known to prevent induction in vivo and the best characterized of these anti-inducers is o-nitrophenyl-fi-D-fucoside [2]. In vitro it has been shown by several techniques that these effectors bind to the lac repressor and that inducers strongly decrease the lac repressor-operator interaction, while in contrast anti-inducers enhance the lac repressor-operator interaction [3 -81. Both types of molecules have no effect on lac repressor-nonoperator DNA interaction (Maurizot, unpublished results). Furthermore kinetic measurements have shown that these ligands act by altering the rate of dissociation of the repressor . operator complex, whereas the rate of association is practically unaffected [7,9]. Recently, the occurrence of a new type of ligand was reported [9]. This neutral ligand, onitrophenyl-8-D-galactoside binds to the lac repressor protein, competes with the inducer isopropyl-P-Dthiogalactoside, but does not affect the interaction of lac repressor with operator DNA. Its binding constant to lac repressor determined by competition experiments is of the same order of magnitude as that of the anti-inducer o-nitrophenyl-P-D-fucoside (9.2 x 103 M-' versus 7.1 x lo3 M-l) [9].We have used the fact that both o-nitrophenyl-/?-D-fucoside and o-nitrophenyl-P-D-galactoside bear a chromophore with an absorption band in the wavelength range 300-400 nm (where the lac repressor does not absorb) to study the interaction between these compounds and the protein, using circular dichroism measurements. It is well recognized that the binding of low-molecular-weight chromophoric substances to macromolecules may generate optical activity [lo-121. In the present case the sugars are by themselves optically active; nevertheless the circular dichroism spectra of the liganded sugars provide an important experimental parameter for analyzing the non-covalent interactions between the effectors and the protein. EXPERIMENTAL PROCEDUREE. coli lac repressor from strain BMH 493 (a gift of Prof. Muller-Hill), was purified by ammonium sulfate fractionation and column chromatography on phosphocellulose ...

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The Composition and Conformation of Sugars in Solution

Cited by 419 publications

References 60 publications

Sodium Ion Interactions with Aqueous Glucose: Insights from Quantum Mechanics, Molecular Dynamics, and Experiment

Sodium Ion Interactions with Aqueous Glucose: Insights from Quantum Mechanics, Molecular Dynamics, and Experiment

C-Nucleosides Derived from Simple Aromatic Hydrocarbons

Circular Dichroism Studies of the Binding of o‐Nitrophenyl‐β‐d‐fucoside and o‐Nitrophenyl‐β‐d‐galactoside to Lac Repressor

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