The recognition of three different epitopes for the H-type 2 human blood group determinant by lections ofUlex europaeus, Galactia tenuiflora andPsophocarpus tetragonolobus (Winged Bean)

1994 ◽  
Vol 11 (5) ◽  
pp. 443-461 ◽  
Author(s):  
Ming-Hui Du ◽  
Ulrike Spohr ◽  
Raymond U. Lemieux
1994 ◽  
Vol 72 (1) ◽  
pp. 158-163 ◽  
Author(s):  
Raymond U. Lemieux ◽  
Ming-Hui Du ◽  
Ulrike Spohr ◽  
Shreeta Acharya ◽  
Avadhesha Surolia

The winged bean acidic lectin (WBA II) binds the H-type 2 human blood group related trisaccharide (α-L-Fuc-(1c → 2b)-β-D-Gal-(1b → 4a)-β-D-GlcNAc-OMe, 1). Interactions that importantly contribute to the specificity of the complex formation are provided by CH2-6b, OH-4b, OH-3b, and OH-2c of 1. On the basis of the relative activities of the monodeoxy and mono-O-methyl derivatives of 1, the hydroxyl groups at the 3a, 6a, and 4c positions become located at the periphery of the combining site, whereas the CH3O-1a, NHAc-2a, and CH3-5c groups are more remote from the protein surface and fully exposed to bulk water. Whereas the WBA II lectin marginally recognizes the H-type 1 related trisaccharide (α-L-Fuc-(1c → 2b)-β-D-Gal-(1b → 3a)-β-D-GlcNAc-OMe, 23), the de-N-acetyl derivative (24) is bound 3.4 times more strongly than 1. This and other results, which are related to changes in interaction between the ligand and the apron of the combining site, are attributed to changes in hydration that lead to enthalpy–entropy compensation. In certain cases, the interactions are found to stabilize the complex.


1992 ◽  
Vol 70 (1) ◽  
pp. 254-271 ◽  
Author(s):  
Ulrike Spohr ◽  
Eugenia Paszkiewicz-Hnatiw ◽  
Naohiko Morishima ◽  
Raymond U. Lemieux

The relative potencies of a wide variety of deoxygenated derivatives of the methyl glycoside of α-L-Fuc-(1 → 2)-β-D-Gal-(1 → 4)- β-D-GlcNAc (the H-type 2 human blood group related trisaccharide) for the inhibition of the binding of an artificial H-type 2 antigen by the lectin I of Ulexeuropaeus confirmed the previous evidence that the key and productive interaction involves only the three hydroxyl groups of the α-L-fucose unit, the hydroxyl at the 3-position of the β-D-galactose residue, and the nonpolar groups in their immediate environment. Except for the acetamido group and the hydroxymethyl of the β-D-Gal unit, which stay in the aqueous phase, on complex formation the remaining three hydroxyl groups appear to come to reside at or near the periphery of the combining site since their replacement by hydrogen causes relatively small changes (< ± 1 kcal/mol) in the stability of the complex (ΔG0). Relatively much larger but compensating changes occur for the enthalpy and entropy terms, and these may arise primarily from the differences in the water structure about the periphery of the combining site and the oligosaccharide both prior to and after complexation. It is proposed that steric constraints lead to an ordered state of the water molecules hydrogen-bonded to the polar groups within the cleft formed by the key region of the amphiphilic combining site. Their release to form less ordered clusters of more strongly hydrogen-bonded water molecules in bulk solution would contribute importantly to the driving force for complexation. It is demonstrated that the surface used for the binding of H-type 2-OMe by a monoclonal anti-H antibody is virtually identical to that used by the Ulex lectin. Keywords: molecular recognition, H-type 2 blood group determinant and deoxygenated derivatives, lectin I of Ulexeuropaeus, anti-H-type 2 monoclonal antibody, enthalpy–entropy compensation.


Tetrahedron ◽  
2006 ◽  
Vol 62 (20) ◽  
pp. 4954-4978 ◽  
Author(s):  
Zhi-Guang Wang ◽  
J. David Warren ◽  
Vadim Y. Dudkin ◽  
Xufang Zhang ◽  
Ulrich Iserloh ◽  
...  

ChemInform ◽  
2010 ◽  
Vol 32 (34) ◽  
pp. no-no
Author(s):  
Zhi-Guang Wang ◽  
Xufang Zhang ◽  
Michael Visser ◽  
David Live ◽  
Andrzej Zatorski ◽  
...  

1985 ◽  
Vol 63 (10) ◽  
pp. 2653-2658 ◽  
Author(s):  
Ole Hindsgaul ◽  
Deveshwari P. Khare ◽  
Mimi Bach ◽  
Raymond U. Lemieux

Using a radioimmunoassay to measure the relative potencies of a wide range of chemically modified structures related to the H-type 2 human blood group determinant, evidence was accumulated that the binding of αLFuc(1→2)βDGal(1→4)-βDGlcNAc-OMe by the lectin I of Ulexeuropaeus involves a wedge-shaped amphiphilic surface which extends on one side of the molecule from the methoxy aglycon to OH-3 of the βDGal unit. A cluster which involves OH-3, OH-4, and OH-2 of the αLFuc unit along with OH-3 of the βDGal unit provides the polar interactions with the lectin. However, only OH-3 and OH-4 of the αLFuc are indispensable to complex formation and are regarded as providing the key polar interaction. The binding reaction involves both a decrease in enthalpy of 29 kcal/mol and a decrease of 68 cal/mol/K in entropy. It is submitted that the main source of the decrease in enthalpy is the establishment of nonpolar interactions that extend from the aglycon over the nonpolar portion of the β-side of the βDGlcNAc unit and on to include a major portion of the α-side of the αLFuc unit. The binding of the βDGlcNAc unit includes OH-6 intramolecularly hydrogen bonded to O-5 in order to extend the nonpolar interactions to the α-side of this unit and perhaps beyond. The decreases in enthalpy (6.0 kcal/mol) and entropy (2.7 cal/mol/K) which occur on the binding of methyl α-L-fucopyranoside are much smaller than for the H-type 2 trisaccharide and are compatible with the much smaller surface that interacts to form the complex. The inhibition data obtained using a range of structures related to methyl α-L-fucopyranoside are in general accord with expectations based on the results obtained with the more complex structures.


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