Cinzia Colombo - Academia.edu (original) (raw)

Papers by Cinzia Colombo

Journal of agricultural and food chemistry, Jan 18, 2015

A practical method for simultaneously quantifying fructose and ethanol contents in wines using (1... more A practical method for simultaneously quantifying fructose and ethanol contents in wines using (13)C quantitative nuclear magnetic resonance (qNMR) spectroscopy is reported. Less than 0.6 mL of wine is needed, and the method leaves an unmodified sample available for subsequent testing or additional analyses. The relative ratios of the five known fructose isomers in ethanolic solutions at different pH and their variations with the temperature are also reported. The data are correlated with the sweetness of wines. The technique was applied to commercially available wines, and the results are compared to other methods. Sugar levels above 0.6 g/L can also be measured. A simple adaptation of the method permits measurement of different carbohydrates using integration of single peaks for each compound, in combination with an external reference (13)C qNMR spectrum of a sample with a known concentration. The method can be applied at all stages of wine production, including grape must, during...

Journal of Agricultural and Food Chemistry, 2015

A practical method for simultaneously quantifying fructose and ethanol contents in wines using (1... more A practical method for simultaneously quantifying fructose and ethanol contents in wines using (13)C quantitative nuclear magnetic resonance (qNMR) spectroscopy is reported. Less than 0.6 mL of wine is needed, and the method leaves an unmodified sample available for subsequent testing or additional analyses. The relative ratios of the five known fructose isomers in ethanolic solutions at different pH and their variations with the temperature are also reported. The data are correlated with the sweetness of wines. The technique was applied to commercially available wines, and the results are compared to other methods. Sugar levels above 0.6 g/L can also be measured. A simple adaptation of the method permits measurement of different carbohydrates using integration of single peaks for each compound, in combination with an external reference (13)C qNMR spectrum of a sample with a known concentration. The method can be applied at all stages of wine production, including grape must, during fermentation, and before and after bottling.

ChemBioChem, 2016

The design of synthetic foldamers to selectively bind proteins is currently hindered by the limit... more The design of synthetic foldamers to selectively bind proteins is currently hindered by the limited availability of molecular data to establish key features of recognition. Previous work has described dimerization of human carbonic anhydrase II (HCA) via self-association of a quinoline oligoamide helical foldamer attached to a tight-binding HCA ligand. A crystal structure of the complex provided atomic details to explain the observed induction of a single foldamer helix handedness, and revealed an unexpected foldamer-mediated dimerization. Here we investigate the detailed behavior of the HCA-foldamer complex in solution by using NMR spectroscopy. We find that the ability to dimerize is buffer dependent and with partially distinct intermolecular contacts. The use of a foldamer variant incapable of self-association confirmed the ability to induce helix handedness separate from dimer formation, and provided insight into the dynamics of enantiomeric selection.

European Journal of Organic Chemistry, 2011

ABSTRACT A practical synthesis of Nα-fluorenylmethoxycarbonyl-Nγ-(2,3,4,6-tetra-O-acetyl-α-D-glyc... more ABSTRACT A practical synthesis of Nα-fluorenylmethoxycarbonyl-Nγ-(2,3,4,6-tetra-O-acetyl-α-D-glycopyranosyl)-L-asparagine in the gluco and galacto series has been achieved by using the methodology developed by DeShong and co-workers. The resulting α-N-linked glycosyl amino acids were used in a linear approach to the synthesis of glycopeptides featuring the unnatural α-N-glycosyl linkage. Activation conditions for both C- and N-terminus elongation in solution have been defined. The main side-reaction encountered was the formation of cyclization by-products (aspartimide) from the activated amino acid during C-terminus elongation. Appropriate condensing agents were identified, which allowed a high yield of dipeptide formation and no epimierization of the glycosyl amino acids. Conditions for sugar deacetylation have also been optimized. Solid-phase synthesis (Fmoc protocol) conditions were explored and PyBROP was found to be the reagent of choice for the activaton of glycosyl amino acids. The synthesis of more complex α-N-linked glycopeptides has thus become feasible, which will allow the properties of these neo-glycoconjugates to be studied.

European Journal of Organic Chemistry, 2014

ABSTRACT For biological applications, the control of the helix handedness of water-soluble quinol... more ABSTRACT For biological applications, the control of the helix handedness of water-soluble quinoline-based oligoamide foldamers has been investigated by the installation of chiral end groups at either the C or N terminus. This has resulted in the development of monomer units capable of unequivocally inducing helical sense without impacting the aqueous solubility. Furthermore, we showed that very slow helix handedness inversion in water can be exploited. The incorporation of a chiral moiety with no handedness-induction properties allows the chromatographic separation of P and M helices as diastereoisomers with kinetically locked handedness.

Molecular Diversity, 2011

In this article, we describe the design, synthesis and activity evaluation of glycomimetic DC-SIG... more In this article, we describe the design, synthesis and activity evaluation of glycomimetic DC-SIGN antagonists, that use a mannose residue to anchor to the protein carbohydrate recognition domain (CRD). The molecules were designed from the structure of the known pseudo-mannobioside antagonist 1, by including additional hydrophobic groups, which were expected to engage lipophilic areas of DC-SIGN CRD. The results demonstrate that the synthesized compounds potently inhibit DC-SIGN-mediated adhesion to mannan coated plates. Additionally, in silico docking studies were performed to rationalize the results and to suggest further optimization.

Organic & Biomolecular Chemistry, 2012

Angewandte Chemie International Edition, 2014

In the search of molecules that could recognize sizeable areas of protein surfaces, a series of t... more In the search of molecules that could recognize sizeable areas of protein surfaces, a series of ten helical aromatic oligoamide foldamers was synthesized on solid phase. The foldamers comprise three to five monomers carrying various proteinogenic side chains, and exist as racemic mixtures of interconverting right-handed and left-handed helices. Functionalization of the foldamers by a nanomolar ligand of human carbonic anhydrase II (HCA) ensured that they would be held in close proximity to the protein surface. Foldamer-protein interactions were screened by circular dichroism (CD). One foldamer displayed intense CD bands indicating that a preferred helix handedness is induced upon interacting with the protein surface. The crystal structure of the complex between this foldamer and HCA could be resolved at 2.1 Å resolution and revealed a number of unanticipated protein-foldamer, foldamer-foldamer, and protein-protein interactions.

Org. Biomol. Chem., 2015

We report a first set of peptidomimetic ligands mimicking the adhesive interface identified by re... more We report a first set of peptidomimetic ligands mimicking the adhesive interface identified by recent crystallographic structures of E-and N-cadherin. Compounds 2 and 3 inhibit adhesion of epithelial ovarian cancer (EOC) cells with improved efficacy compared to the ADH-1 peptide, a N-cadherin antagonist that is in early clinical trials in EOC patients.

Journal of agricultural and food chemistry, Jan 18, 2015

A practical method for simultaneously quantifying fructose and ethanol contents in wines using (1... more A practical method for simultaneously quantifying fructose and ethanol contents in wines using (13)C quantitative nuclear magnetic resonance (qNMR) spectroscopy is reported. Less than 0.6 mL of wine is needed, and the method leaves an unmodified sample available for subsequent testing or additional analyses. The relative ratios of the five known fructose isomers in ethanolic solutions at different pH and their variations with the temperature are also reported. The data are correlated with the sweetness of wines. The technique was applied to commercially available wines, and the results are compared to other methods. Sugar levels above 0.6 g/L can also be measured. A simple adaptation of the method permits measurement of different carbohydrates using integration of single peaks for each compound, in combination with an external reference (13)C qNMR spectrum of a sample with a known concentration. The method can be applied at all stages of wine production, including grape must, during...

Journal of Agricultural and Food Chemistry, 2015

A practical method for simultaneously quantifying fructose and ethanol contents in wines using (1... more A practical method for simultaneously quantifying fructose and ethanol contents in wines using (13)C quantitative nuclear magnetic resonance (qNMR) spectroscopy is reported. Less than 0.6 mL of wine is needed, and the method leaves an unmodified sample available for subsequent testing or additional analyses. The relative ratios of the five known fructose isomers in ethanolic solutions at different pH and their variations with the temperature are also reported. The data are correlated with the sweetness of wines. The technique was applied to commercially available wines, and the results are compared to other methods. Sugar levels above 0.6 g/L can also be measured. A simple adaptation of the method permits measurement of different carbohydrates using integration of single peaks for each compound, in combination with an external reference (13)C qNMR spectrum of a sample with a known concentration. The method can be applied at all stages of wine production, including grape must, during fermentation, and before and after bottling.

ChemBioChem, 2016

The design of synthetic foldamers to selectively bind proteins is currently hindered by the limit... more The design of synthetic foldamers to selectively bind proteins is currently hindered by the limited availability of molecular data to establish key features of recognition. Previous work has described dimerization of human carbonic anhydrase II (HCA) via self-association of a quinoline oligoamide helical foldamer attached to a tight-binding HCA ligand. A crystal structure of the complex provided atomic details to explain the observed induction of a single foldamer helix handedness, and revealed an unexpected foldamer-mediated dimerization. Here we investigate the detailed behavior of the HCA-foldamer complex in solution by using NMR spectroscopy. We find that the ability to dimerize is buffer dependent and with partially distinct intermolecular contacts. The use of a foldamer variant incapable of self-association confirmed the ability to induce helix handedness separate from dimer formation, and provided insight into the dynamics of enantiomeric selection.

European Journal of Organic Chemistry, 2011

ABSTRACT A practical synthesis of Nα-fluorenylmethoxycarbonyl-Nγ-(2,3,4,6-tetra-O-acetyl-α-D-glyc... more ABSTRACT A practical synthesis of Nα-fluorenylmethoxycarbonyl-Nγ-(2,3,4,6-tetra-O-acetyl-α-D-glycopyranosyl)-L-asparagine in the gluco and galacto series has been achieved by using the methodology developed by DeShong and co-workers. The resulting α-N-linked glycosyl amino acids were used in a linear approach to the synthesis of glycopeptides featuring the unnatural α-N-glycosyl linkage. Activation conditions for both C- and N-terminus elongation in solution have been defined. The main side-reaction encountered was the formation of cyclization by-products (aspartimide) from the activated amino acid during C-terminus elongation. Appropriate condensing agents were identified, which allowed a high yield of dipeptide formation and no epimierization of the glycosyl amino acids. Conditions for sugar deacetylation have also been optimized. Solid-phase synthesis (Fmoc protocol) conditions were explored and PyBROP was found to be the reagent of choice for the activaton of glycosyl amino acids. The synthesis of more complex α-N-linked glycopeptides has thus become feasible, which will allow the properties of these neo-glycoconjugates to be studied.

European Journal of Organic Chemistry, 2014

ABSTRACT For biological applications, the control of the helix handedness of water-soluble quinol... more ABSTRACT For biological applications, the control of the helix handedness of water-soluble quinoline-based oligoamide foldamers has been investigated by the installation of chiral end groups at either the C or N terminus. This has resulted in the development of monomer units capable of unequivocally inducing helical sense without impacting the aqueous solubility. Furthermore, we showed that very slow helix handedness inversion in water can be exploited. The incorporation of a chiral moiety with no handedness-induction properties allows the chromatographic separation of P and M helices as diastereoisomers with kinetically locked handedness.

Molecular Diversity, 2011

In this article, we describe the design, synthesis and activity evaluation of glycomimetic DC-SIG... more In this article, we describe the design, synthesis and activity evaluation of glycomimetic DC-SIGN antagonists, that use a mannose residue to anchor to the protein carbohydrate recognition domain (CRD). The molecules were designed from the structure of the known pseudo-mannobioside antagonist 1, by including additional hydrophobic groups, which were expected to engage lipophilic areas of DC-SIGN CRD. The results demonstrate that the synthesized compounds potently inhibit DC-SIGN-mediated adhesion to mannan coated plates. Additionally, in silico docking studies were performed to rationalize the results and to suggest further optimization.

Organic & Biomolecular Chemistry, 2012

Angewandte Chemie International Edition, 2014

In the search of molecules that could recognize sizeable areas of protein surfaces, a series of t... more In the search of molecules that could recognize sizeable areas of protein surfaces, a series of ten helical aromatic oligoamide foldamers was synthesized on solid phase. The foldamers comprise three to five monomers carrying various proteinogenic side chains, and exist as racemic mixtures of interconverting right-handed and left-handed helices. Functionalization of the foldamers by a nanomolar ligand of human carbonic anhydrase II (HCA) ensured that they would be held in close proximity to the protein surface. Foldamer-protein interactions were screened by circular dichroism (CD). One foldamer displayed intense CD bands indicating that a preferred helix handedness is induced upon interacting with the protein surface. The crystal structure of the complex between this foldamer and HCA could be resolved at 2.1 Å resolution and revealed a number of unanticipated protein-foldamer, foldamer-foldamer, and protein-protein interactions.

Org. Biomol. Chem., 2015

We report a first set of peptidomimetic ligands mimicking the adhesive interface identified by re... more We report a first set of peptidomimetic ligands mimicking the adhesive interface identified by recent crystallographic structures of E-and N-cadherin. Compounds 2 and 3 inhibit adhesion of epithelial ovarian cancer (EOC) cells with improved efficacy compared to the ADH-1 peptide, a N-cadherin antagonist that is in early clinical trials in EOC patients.