Dale Cumming - Academia.edu (original) (raw)
Papers by Dale Cumming
Novartis Foundation Symposia, 2007
For carbohydrates to serve as recognition elements in cellular function, there must be 'recep... more For carbohydrates to serve as recognition elements in cellular function, there must be 'receptors' which are capable of distinguishing between the multitude of oligosaccharide structures generated by a cell. Generally these receptors are assumed to be proteins, and the plant lectins have been used as model systems to examine the molecular basis for specificity in such interactions. Three aspects of the specificity of oligosaccharide-protein interactions will be discussed: (1) the conformational flexibility of oligosaccharides will be demonstrated through a quantitative analysis of nuclear magnetic resonance measurements; (2) a comparison of the measured and calculated values for the entropy barrier to oligosaccharide binding will be used to argue that the barrier arises from a loss of this conformational flexibility upon binding to the lectin (this conclusion is also supported by X-ray crystallographic studies); and (3) the thermodynamic model can be extended to the binding of glycoproteins to receptors and the high affinity of these interactions explained by either multivalency or fixation of the oligosaccharide in the 'correct' three-dimensional structure through interaction with the protein moiety.
CIBA Foundation Symposium, Nov 15, 1988
Developments in biological standardization, 1992
The glycosylation of proteins is a complex biological pathway which is ordered and non-random. It... more The glycosylation of proteins is a complex biological pathway which is ordered and non-random. It is also a deterministic pathway dependent upon protein sequence, cellular phenotype, and the physiological environment. Two principal physiological roles have emerged within the past decade for protein-linked glycans: as recognition determinants and as modulators of various protein attributes such as bioactivity, pharmacokinetics, folding, and immunogenicity. All these attributes are crucial to development and application of protein-based pharmaceuticals. However, protein glycosylation represents a difficult structure/function problem since most glycoproteins exhibit microheterogeneity and oligosaccharides frequently contribute to this heterogeneity. Nevertheless, recent data suggest that different members of the heterogeneous ensemble exhibit distinguishable intrinsic properties, suggesting that the microheterogeneity of protein glycosylation represents a sophisticated mechanism of bio...
Journal of Immunology, Jul 1, 1996
Adhesion through the LFA-1 (CD11a/CD18)-ICAM-1 (CD54) and the VLA-4 (CD49d)-VCAM-1 (CD106) pathwa... more Adhesion through the LFA-1 (CD11a/CD18)-ICAM-1 (CD54) and the VLA-4 (CD49d)-VCAM-1 (CD106) pathways prevents apoptosis of germinal center B cells.
Nouvelle glycoproteine ligand de P-selectine, qui comporte la sequence d'acides amines presen... more Nouvelle glycoproteine ligand de P-selectine, qui comporte la sequence d'acides amines presentee dans SEQ ID NO:2 ou par la sequence d'acides amines presentee dans SEQ ID NO:4. Des sequences d'ADN codant la proteine ligand de P-selectine sont egalement decrites, ainsi que des vecteurs, des cellules hotes et des procedes permettant de fabriquer ladite proteine ligand de P-selectine. Des compositions pharmaceutiques contenant cette proteine et des procedes de traitement d'etats inflammatoires caracterises par des adherences intercellulaires induites par la P-selectine et la E-selectine sont egalement decrites.
The American journal of pathology, 1996
It has been postulated that endothelial cell adhesion molecules involved in leukocyte recruitment... more It has been postulated that endothelial cell adhesion molecules involved in leukocyte recruitment play a role in metastasis. Using an in vitro flow model, we studied the adhesion of the human colon carcinoma cell line KM12-L4 to P-selectin, an inducible endothelial-expressed adhesion molecule involved in leukocyte recruitment. Recombinant forms of P-selectin and Chinese hamster ovary cells stably expressing P-selectin supported attachment and rolling of KM12-L4 cells at 1 to 2 dynes/cm2. The adhesive interactions to P-selectin were abolished by pretreatment of the KM12-L4 cells with neuraminidase but were unaltered by pretreatment of the KM12-L4 cells with O-sialoglycoprotein endopeptidase, an enzyme that cleaves mucin type glycoproteins such as P-selectin glycoprotein ligand-1 (PSGL-1). PSGL-1 is the only counter-receptor for P-selectin known to mediate myeloid cell adhesion to P-selectin under flow. Flow cytometric and Northern blot analyses revealed that KM12-L4 cells did not exp...
Canadian Journal of Chemistry, 1990
We describe a simple and efficient method for the preparation of the trisaccharide GlcNAc(β1-4)-[... more We describe a simple and efficient method for the preparation of the trisaccharide GlcNAc(β1-4)-[Fuc(α 1-6)-]GlcNAc(β 1-) (1) and of the protected form of GlcNAc(β 1-4)-[Fuc(α 1-6)-]GlcNAc(β1-Asn) (2). The key intermediate is benzyl 4,6-benzylidene chitobioside 5 giving the desired trisaccharide by insitu anomerization–glycosylation reaction with 2,3,4-tribenzylfucosyl bromide. The benzyl glycoside in the trisaccharide 6 has been replaced by acetate and then bromine; this glycosylating agent was used to prepare methyl and 8-methoxycarbonyloctyl glycosides as well as isothiocyanate 12, in a series of reactions. The latter compound gave, on reaction with 1-benzyl N-benzyloxycarbonyl-L-asparate, compound 13 (a protected derivative of 2), which should serve as a synthon for syntheses of glycopeptides. Keywords: glycopeptide, synthesis; oligosaccharide, synthesis; chitobiosides; fucosylated chitobiosides; N-linked oligosaccharides.
L'invention concerne un nouveau mutant d'acides nucleiques 2 GlcNAcT de nucleocapside, de... more L'invention concerne un nouveau mutant d'acides nucleiques 2 GlcNAcT de nucleocapside, des polypeptides codees par les acides nucleiques et leurs utilisations.
Biochemistry
A major periodate-Schiff-positive component from milk-fat-globule membrane of human breast milk h... more A major periodate-Schiff-positive component from milk-fat-globule membrane of human breast milk has been purified by selectively extracting the membrane glycoproteins, followed by lectin affinity chromatography and gel filtration on Sephadex G-200 in the presence of protein-dissociating agents. The purified glycoprotein, termed epithelial membrane glycoprotein (EMGP-70), has an estimated mol.wt. of 70000 and yields a single band under reducing conditions on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The glycoprotein contains 13.5% carbohydrate by weight, with fucose, mannose, galactose, N-acetylglucosamine and sialic acid 17.2,17.0, 21.1, 7.9 and 36.6% respectively of the carbohydrate moiety. Aspartic and glutamic acid and serine are the major amino acid residues.
Journal of Biological Chemistry, 1981
Journal of Biological Chemistry, 1986
Novartis Foundation Symposia, 2007
For carbohydrates to serve as recognition elements in cellular function, there must be 'recep... more For carbohydrates to serve as recognition elements in cellular function, there must be 'receptors' which are capable of distinguishing between the multitude of oligosaccharide structures generated by a cell. Generally these receptors are assumed to be proteins, and the plant lectins have been used as model systems to examine the molecular basis for specificity in such interactions. Three aspects of the specificity of oligosaccharide-protein interactions will be discussed: (1) the conformational flexibility of oligosaccharides will be demonstrated through a quantitative analysis of nuclear magnetic resonance measurements; (2) a comparison of the measured and calculated values for the entropy barrier to oligosaccharide binding will be used to argue that the barrier arises from a loss of this conformational flexibility upon binding to the lectin (this conclusion is also supported by X-ray crystallographic studies); and (3) the thermodynamic model can be extended to the binding of glycoproteins to receptors and the high affinity of these interactions explained by either multivalency or fixation of the oligosaccharide in the 'correct' three-dimensional structure through interaction with the protein moiety.
CIBA Foundation Symposium, Nov 15, 1988
Developments in biological standardization, 1992
The glycosylation of proteins is a complex biological pathway which is ordered and non-random. It... more The glycosylation of proteins is a complex biological pathway which is ordered and non-random. It is also a deterministic pathway dependent upon protein sequence, cellular phenotype, and the physiological environment. Two principal physiological roles have emerged within the past decade for protein-linked glycans: as recognition determinants and as modulators of various protein attributes such as bioactivity, pharmacokinetics, folding, and immunogenicity. All these attributes are crucial to development and application of protein-based pharmaceuticals. However, protein glycosylation represents a difficult structure/function problem since most glycoproteins exhibit microheterogeneity and oligosaccharides frequently contribute to this heterogeneity. Nevertheless, recent data suggest that different members of the heterogeneous ensemble exhibit distinguishable intrinsic properties, suggesting that the microheterogeneity of protein glycosylation represents a sophisticated mechanism of bio...
Journal of Immunology, Jul 1, 1996
Adhesion through the LFA-1 (CD11a/CD18)-ICAM-1 (CD54) and the VLA-4 (CD49d)-VCAM-1 (CD106) pathwa... more Adhesion through the LFA-1 (CD11a/CD18)-ICAM-1 (CD54) and the VLA-4 (CD49d)-VCAM-1 (CD106) pathways prevents apoptosis of germinal center B cells.
Nouvelle glycoproteine ligand de P-selectine, qui comporte la sequence d'acides amines presen... more Nouvelle glycoproteine ligand de P-selectine, qui comporte la sequence d'acides amines presentee dans SEQ ID NO:2 ou par la sequence d'acides amines presentee dans SEQ ID NO:4. Des sequences d'ADN codant la proteine ligand de P-selectine sont egalement decrites, ainsi que des vecteurs, des cellules hotes et des procedes permettant de fabriquer ladite proteine ligand de P-selectine. Des compositions pharmaceutiques contenant cette proteine et des procedes de traitement d'etats inflammatoires caracterises par des adherences intercellulaires induites par la P-selectine et la E-selectine sont egalement decrites.
The American journal of pathology, 1996
It has been postulated that endothelial cell adhesion molecules involved in leukocyte recruitment... more It has been postulated that endothelial cell adhesion molecules involved in leukocyte recruitment play a role in metastasis. Using an in vitro flow model, we studied the adhesion of the human colon carcinoma cell line KM12-L4 to P-selectin, an inducible endothelial-expressed adhesion molecule involved in leukocyte recruitment. Recombinant forms of P-selectin and Chinese hamster ovary cells stably expressing P-selectin supported attachment and rolling of KM12-L4 cells at 1 to 2 dynes/cm2. The adhesive interactions to P-selectin were abolished by pretreatment of the KM12-L4 cells with neuraminidase but were unaltered by pretreatment of the KM12-L4 cells with O-sialoglycoprotein endopeptidase, an enzyme that cleaves mucin type glycoproteins such as P-selectin glycoprotein ligand-1 (PSGL-1). PSGL-1 is the only counter-receptor for P-selectin known to mediate myeloid cell adhesion to P-selectin under flow. Flow cytometric and Northern blot analyses revealed that KM12-L4 cells did not exp...
Canadian Journal of Chemistry, 1990
We describe a simple and efficient method for the preparation of the trisaccharide GlcNAc(β1-4)-[... more We describe a simple and efficient method for the preparation of the trisaccharide GlcNAc(β1-4)-[Fuc(α 1-6)-]GlcNAc(β 1-) (1) and of the protected form of GlcNAc(β 1-4)-[Fuc(α 1-6)-]GlcNAc(β1-Asn) (2). The key intermediate is benzyl 4,6-benzylidene chitobioside 5 giving the desired trisaccharide by insitu anomerization–glycosylation reaction with 2,3,4-tribenzylfucosyl bromide. The benzyl glycoside in the trisaccharide 6 has been replaced by acetate and then bromine; this glycosylating agent was used to prepare methyl and 8-methoxycarbonyloctyl glycosides as well as isothiocyanate 12, in a series of reactions. The latter compound gave, on reaction with 1-benzyl N-benzyloxycarbonyl-L-asparate, compound 13 (a protected derivative of 2), which should serve as a synthon for syntheses of glycopeptides. Keywords: glycopeptide, synthesis; oligosaccharide, synthesis; chitobiosides; fucosylated chitobiosides; N-linked oligosaccharides.
L'invention concerne un nouveau mutant d'acides nucleiques 2 GlcNAcT de nucleocapside, de... more L'invention concerne un nouveau mutant d'acides nucleiques 2 GlcNAcT de nucleocapside, des polypeptides codees par les acides nucleiques et leurs utilisations.
Biochemistry
A major periodate-Schiff-positive component from milk-fat-globule membrane of human breast milk h... more A major periodate-Schiff-positive component from milk-fat-globule membrane of human breast milk has been purified by selectively extracting the membrane glycoproteins, followed by lectin affinity chromatography and gel filtration on Sephadex G-200 in the presence of protein-dissociating agents. The purified glycoprotein, termed epithelial membrane glycoprotein (EMGP-70), has an estimated mol.wt. of 70000 and yields a single band under reducing conditions on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The glycoprotein contains 13.5% carbohydrate by weight, with fucose, mannose, galactose, N-acetylglucosamine and sialic acid 17.2,17.0, 21.1, 7.9 and 36.6% respectively of the carbohydrate moiety. Aspartic and glutamic acid and serine are the major amino acid residues.
Journal of Biological Chemistry, 1981
Journal of Biological Chemistry, 1986