Cornelis P.J. Glaudemans

The chloroacetyl group in synthetic carbohydrate chemistry

Abstract A number of O -chloroacetyl derivatives of d -glucose have been prepared. They crystallize with ease, and, as the chloroacetyl group can be removed with facility by treatment with thiourea to yield the parent carbohydrate derivative, they serve as valuable tools in synthetic carbohydrate chemistry. To illustrate this, we have prepared 1- O -benzoyl-β- d -glucopyranose by reductive debenzylation of benzyl 2,3,4,6-tetra- O -(chloroacetyl)-β- d -glucopyranoside followed by benzoylation, and removal of the chloroacetyl groups with thiourea. An alternative route was by chromium trioxide oxidation of benzyl 2,3,4,6-tetra- O -(chloroacetyl)-β- d -glucopyranoside to 1- O -benzoyltetra- O -(chloroacetyl)-β- d -glucopyranose, followed by removal of the chloroacetyl groups with thiourea.

Galactofuranosyl groups are immunodominant in Aspergillus fumigatus galactomannan

Aspergillus fumigatus galactomannan was prepared and its structure partially characterized. Galactofuranosyl groups were immunodominant when this polysaccharide antigen was reacted with antibody raised in rabbits.

The structure of the capsular polysaccharide from crytococcus neoformans serotype d

The capsular polysaccharide from Cryptococcus neoformans serotype D has been studied by employing the usual methods for the elucidation of chemical structure. The results are consistent with the occurrence of a polysaccharide having both D-glucosyl-uronic acid and D-xylosyl groups present as nonreducing end-groups attached to O-2 of D-mannosyl residues which are linked alpha-D-(1 leads to 3) in a linear backbone.

A hypothetical space-filling model of the V-regions of the galactan-binding myeloma immunoglobulin J539

Abstract J539 is an IgA myeloma protein whose V-region amino acid sequences and ligand binding for β-1.6-galactosyl oligosaccharides have been determined in the past. Two hypothetical, three-dimensional models of this protein have now been constructed on a computer display system by modifying the known structures of McPC603. The J539 Fv is 11 amino acids shorter than McPC603, and its χ-carbon backbone was formed by eliminating positions from McPC603 and rejoining the chains at three deletion sites in CDR-1 of V L and CDR-2 and -3 of V H . This maneuver was performed using a three-dimensional viewing system that displayed the amino acids with side chains in the regions around the break sites. The side chains of the amino acids in the model were oriented by a computer program that searched the available space for positions that did not make van der Waals contacts with neighboring atoms. β-1,6-Galactohexaose has been fitted to the J539 combining site using the computer display system. The terminal non-reducing sugar made close contacts with hydrogen bond accepting amino acids in CDR-2 of V H and oxygens of the third and fourth sugars were close to hydrogen bond accepting amino acids in CDR-1 and CDR-3 of V L . While the proposed structures are not unique solutions for J539 they present working models for further immunochemical experiments.

On the structure of the capsular polysaccharide from Cryptococcus neoformans serotype c—II

Abstract Further examination of the capsular polysaccharide of Cryptococcus neoformans serotype C by alkaline degradation and methylation, followed by hydrolysis, has shown that the glucuronic acid residues in the polysaccharides are located on the mannose residue already substituted with xylose. In addition, the anomeric configuration of the sugars has been confirmed by 1H NMR spectroscopy.

The Interaction of Homogeneous, Murine Myeloma Immunoglobulins with Polysaccharide Antigens°

Publisher Summary A new potential in polysaccharide immunochemistry is provided by homogeneous immunoglobulin that bind carbohydrate polymers.In the chapter, the specific immunoglobulin-hapten interaction is discussed and characterized. The discipline of carbohydrate chemistry can make a real contribution to the elucidation of the structure of immunoglobulin. In return, carbohydrate chemistry may find a tool that can be increasingly applied to the unraveling of its own unsolved problems in the structural analysis of polysaccharides. The chapter discusses the structure of immunoglobulins. The cellular component of the immune system that synthesizes and secretes immunoglobulin differentiates in a highly specialized way. The largest groups of anticarbohydrate, myeloma immunoglobulins are that of antifructans having specificity for β-D-(2 →1)-linkages. It is convenient to combine the discussion of this group with that of the anti-(2 →6)-β–D-fructan immunoglobulins.

Structural studies on the major, capsular polysaccharide from Cryptococcus bacillisporus serotype B.

The capsular material from Cryptococcus bacillisporus serotype B has been separated into essentially two fractions. One of these (60% of the total) has been studied by the methods usual for the structural elucidation of polysaccharides. The results are consistent with a structure having nonreducing D-xylosyl as well as D-glucosyluronic acid groups attached to O-2 of D-mannosyl residues linked alpha-(1 leads to 3) in a linear backbone. Every third D-mannosyl residue is doubly substituted with a D-xylosyl group at O-2 and a D-glucosyluronic acid group at O-4.

Capsular polysaccharides from a parent strain and from a possible, mutant strain of Cryptococcus neoformans serotype A.

Abstract The capsular polysaccharides from Cryptococcus neoformans serotype A and from a possible, mutant strain thereof have been structurally analyzed. The latter material is similar to the capsular antigen of C. neoformans serotype D.

Synthesis and characterization of methyl 6-O-α- and -β-d-galactopyranosyl-β-d-galactopyranoside

Abstract Sequential tritylation, acetylation and detritylation of methyl β- d -galactopyranoside gave crystalline methyl 2,3,4-tri- O -acetyl-β- d -galactopyranoside ( 4 ) and methyl 2,3,6-tri- O -acetyl-β- d -galactopyranoside, the latter being the minor product resulting from acetyl migration. Reaction of 4 with 2,3,4,6-tetra- O -acetyl-α- d -galactosyl bromide in benzene, in the presence of mercuric cyanide and mercuric bromide, gave the α- and β- d -(1→6)-linked disaccharides ( 7 and 9 , respectively) in high yield, and their structure was confirmed by 1 H- and 13 C-n.m.r. 1d. and 2d. spectroscopy. O -Deacetylation of 7 gave the hitherto unknown, crystalline methyl 6- O -α- d -galactopyranosyl-β- d -galactopyranoside. O -Deacetylation of 9 gave the corresponding, β- d -linked disaccharide methyl glycoside, the physical constants of which are discussed with respect to controversial data in the literature.

Binding studies on a mouse-myeloma immunoglobulin a having specificity for β-D-(1→6)-linked D-galactopyranosyl residues

Abstract The free energies of binding between immunoglobulin A J 539 (Fab′) and methyl 6- O -acetyl-β- D -galactopyranoside ( 1 ) and 6- O -β- D -galactopyranosyl-1,2:3,4-di- O -isopropylidene-α- D -galactopyranose ( 2 ) have been measured. The values found suggest that bulky substitution on O′-6 or O-1, O-2, O-3, and O-4 in the hapten 6- O -β- D -galactopyranosyl- D -galactose ( 3 ) does not interfere with effective binding of that ligand and the immunoglobulin. This conclusion supports the postulations that ( a ) the ligand 3 binds only on one side of the molecule, and ( b ) the combining site of the immunoglobulin J 539 appears to be located on an exposed surface area.