Differences in the binding affinities of dimeric concanavalin A (including acetyl and succinyl derivatives) and tetrameric concanavalin A with large oligomannose-type glycopeptides

Dipak K. Mandai, Curtis F. Brewer

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Abstract

Dimeric derivatives of concanavalin A (Con A) such as acetyl- and succinyl-Con A have been used for years as probes of cellular membranes. The altered binding and biological activities of these derivatives relative to native tetrameric Con A have generally been attributed to their reduced valence. However, the present study shows that acetyl- and succinyl-Con A possess lower affinities than tetrameric Con A toward certain oligomannose-type glycopeptides which are found on the surface of cells. It has previously been shown that native tetrameric Con A possesses 5-30-fold enhanced affinities toward Man7-Man9 oligomannose-type glycopeptides, respectively, relative to Man5 and Man6 oligomannose-type glycopeptides [Bhattacharyya, L., & Brewer, C. F. (1989) Eur. J. Biochem. 178, 721-726]. Using titration microcalorimetry and hemagglutination inhibition measurements, methyl α-D-mannopyranoside, methyl 3,6-di-O-(α-D-mannopyranosyl)-α-D-mannopyranoside (which binds with about 60-fold higher affinity than methyl α-D-mannopyranoside and is the major Con A binding epitope on oligomannose-type carbohydrates), and a Man5 oligomannose-type oligosaccharide are shown to bind to underivatized dimeric Con A at pH 5.2 and acetyl- and succinyl-Con A at pH 7.2 with affinities equal to those of native tetrameric Con A. However, a mixture of Man7 and Man8 glycopeptides and a Man9 oligomannose-type glycopeptide were shown to bind to underivatized dimeric Con A and acetyl- and succinyl-Con A with affinities only about 2-fold higher than the Man5 oligosaccharide, in contrast to the higher affinities of native tetrameric Con A for these carbohydrates. Thus, Man7-Man9 oligomannose-type glycopeptides bind with approximately 4- and 10-fold lower affinities, respectively, to dimeric Con A and its derivatives relative to tetrameric Con A. Differences in the affinities of dimeric and tetrameric Con A for the larger oligomannose-type glycopeptides are ascribed to the ability of the longer α(1-3) and α(1-6) arms of the Man7-Man9 glycopeptides to "jump" between adjacent monomer binding sites of the tetramer before dissociating from the protein and the absence of this effect in the dimer where the binding sites are further separated. The present findings indicate that acetyl- and succinyl-Con A can not be used as mere "divalent" derivatives of the lectin in studies of cell membranes which possess Man7-Man9 oligomannose-type carbohydrates.

Original languageEnglish (US)
Pages (from-to)5116-5120
Number of pages5
JournalBiochemistry
Volume32
Issue number19
StatePublished - 1993

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Glycopeptides
Concanavalin A
Derivatives
Carbohydrates
Oligosaccharides
Binding Sites
Hemagglutination
Cell membranes
Mannose
Bioactivity
Titration
Lectins
Dimers
Epitopes
Monomers
Cell Membrane
succinylconcanavalin A
Membranes

ASJC Scopus subject areas

  • Biochemistry

Cite this

@article{c549a158120743f0b48bc05f18e4639a,
title = "Differences in the binding affinities of dimeric concanavalin A (including acetyl and succinyl derivatives) and tetrameric concanavalin A with large oligomannose-type glycopeptides",
abstract = "Dimeric derivatives of concanavalin A (Con A) such as acetyl- and succinyl-Con A have been used for years as probes of cellular membranes. The altered binding and biological activities of these derivatives relative to native tetrameric Con A have generally been attributed to their reduced valence. However, the present study shows that acetyl- and succinyl-Con A possess lower affinities than tetrameric Con A toward certain oligomannose-type glycopeptides which are found on the surface of cells. It has previously been shown that native tetrameric Con A possesses 5-30-fold enhanced affinities toward Man7-Man9 oligomannose-type glycopeptides, respectively, relative to Man5 and Man6 oligomannose-type glycopeptides [Bhattacharyya, L., & Brewer, C. F. (1989) Eur. J. Biochem. 178, 721-726]. Using titration microcalorimetry and hemagglutination inhibition measurements, methyl α-D-mannopyranoside, methyl 3,6-di-O-(α-D-mannopyranosyl)-α-D-mannopyranoside (which binds with about 60-fold higher affinity than methyl α-D-mannopyranoside and is the major Con A binding epitope on oligomannose-type carbohydrates), and a Man5 oligomannose-type oligosaccharide are shown to bind to underivatized dimeric Con A at pH 5.2 and acetyl- and succinyl-Con A at pH 7.2 with affinities equal to those of native tetrameric Con A. However, a mixture of Man7 and Man8 glycopeptides and a Man9 oligomannose-type glycopeptide were shown to bind to underivatized dimeric Con A and acetyl- and succinyl-Con A with affinities only about 2-fold higher than the Man5 oligosaccharide, in contrast to the higher affinities of native tetrameric Con A for these carbohydrates. Thus, Man7-Man9 oligomannose-type glycopeptides bind with approximately 4- and 10-fold lower affinities, respectively, to dimeric Con A and its derivatives relative to tetrameric Con A. Differences in the affinities of dimeric and tetrameric Con A for the larger oligomannose-type glycopeptides are ascribed to the ability of the longer α(1-3) and α(1-6) arms of the Man7-Man9 glycopeptides to {"}jump{"} between adjacent monomer binding sites of the tetramer before dissociating from the protein and the absence of this effect in the dimer where the binding sites are further separated. The present findings indicate that acetyl- and succinyl-Con A can not be used as mere {"}divalent{"} derivatives of the lectin in studies of cell membranes which possess Man7-Man9 oligomannose-type carbohydrates.",
author = "Mandai, {Dipak K.} and Brewer, {Curtis F.}",
year = "1993",
language = "English (US)",
volume = "32",
pages = "5116--5120",
journal = "Biochemistry",
issn = "0006-2960",
publisher = "American Chemical Society",
number = "19",

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TY - JOUR

T1 - Differences in the binding affinities of dimeric concanavalin A (including acetyl and succinyl derivatives) and tetrameric concanavalin A with large oligomannose-type glycopeptides

AU - Mandai, Dipak K.

AU - Brewer, Curtis F.

PY - 1993

Y1 - 1993

N2 - Dimeric derivatives of concanavalin A (Con A) such as acetyl- and succinyl-Con A have been used for years as probes of cellular membranes. The altered binding and biological activities of these derivatives relative to native tetrameric Con A have generally been attributed to their reduced valence. However, the present study shows that acetyl- and succinyl-Con A possess lower affinities than tetrameric Con A toward certain oligomannose-type glycopeptides which are found on the surface of cells. It has previously been shown that native tetrameric Con A possesses 5-30-fold enhanced affinities toward Man7-Man9 oligomannose-type glycopeptides, respectively, relative to Man5 and Man6 oligomannose-type glycopeptides [Bhattacharyya, L., & Brewer, C. F. (1989) Eur. J. Biochem. 178, 721-726]. Using titration microcalorimetry and hemagglutination inhibition measurements, methyl α-D-mannopyranoside, methyl 3,6-di-O-(α-D-mannopyranosyl)-α-D-mannopyranoside (which binds with about 60-fold higher affinity than methyl α-D-mannopyranoside and is the major Con A binding epitope on oligomannose-type carbohydrates), and a Man5 oligomannose-type oligosaccharide are shown to bind to underivatized dimeric Con A at pH 5.2 and acetyl- and succinyl-Con A at pH 7.2 with affinities equal to those of native tetrameric Con A. However, a mixture of Man7 and Man8 glycopeptides and a Man9 oligomannose-type glycopeptide were shown to bind to underivatized dimeric Con A and acetyl- and succinyl-Con A with affinities only about 2-fold higher than the Man5 oligosaccharide, in contrast to the higher affinities of native tetrameric Con A for these carbohydrates. Thus, Man7-Man9 oligomannose-type glycopeptides bind with approximately 4- and 10-fold lower affinities, respectively, to dimeric Con A and its derivatives relative to tetrameric Con A. Differences in the affinities of dimeric and tetrameric Con A for the larger oligomannose-type glycopeptides are ascribed to the ability of the longer α(1-3) and α(1-6) arms of the Man7-Man9 glycopeptides to "jump" between adjacent monomer binding sites of the tetramer before dissociating from the protein and the absence of this effect in the dimer where the binding sites are further separated. The present findings indicate that acetyl- and succinyl-Con A can not be used as mere "divalent" derivatives of the lectin in studies of cell membranes which possess Man7-Man9 oligomannose-type carbohydrates.

AB - Dimeric derivatives of concanavalin A (Con A) such as acetyl- and succinyl-Con A have been used for years as probes of cellular membranes. The altered binding and biological activities of these derivatives relative to native tetrameric Con A have generally been attributed to their reduced valence. However, the present study shows that acetyl- and succinyl-Con A possess lower affinities than tetrameric Con A toward certain oligomannose-type glycopeptides which are found on the surface of cells. It has previously been shown that native tetrameric Con A possesses 5-30-fold enhanced affinities toward Man7-Man9 oligomannose-type glycopeptides, respectively, relative to Man5 and Man6 oligomannose-type glycopeptides [Bhattacharyya, L., & Brewer, C. F. (1989) Eur. J. Biochem. 178, 721-726]. Using titration microcalorimetry and hemagglutination inhibition measurements, methyl α-D-mannopyranoside, methyl 3,6-di-O-(α-D-mannopyranosyl)-α-D-mannopyranoside (which binds with about 60-fold higher affinity than methyl α-D-mannopyranoside and is the major Con A binding epitope on oligomannose-type carbohydrates), and a Man5 oligomannose-type oligosaccharide are shown to bind to underivatized dimeric Con A at pH 5.2 and acetyl- and succinyl-Con A at pH 7.2 with affinities equal to those of native tetrameric Con A. However, a mixture of Man7 and Man8 glycopeptides and a Man9 oligomannose-type glycopeptide were shown to bind to underivatized dimeric Con A and acetyl- and succinyl-Con A with affinities only about 2-fold higher than the Man5 oligosaccharide, in contrast to the higher affinities of native tetrameric Con A for these carbohydrates. Thus, Man7-Man9 oligomannose-type glycopeptides bind with approximately 4- and 10-fold lower affinities, respectively, to dimeric Con A and its derivatives relative to tetrameric Con A. Differences in the affinities of dimeric and tetrameric Con A for the larger oligomannose-type glycopeptides are ascribed to the ability of the longer α(1-3) and α(1-6) arms of the Man7-Man9 glycopeptides to "jump" between adjacent monomer binding sites of the tetramer before dissociating from the protein and the absence of this effect in the dimer where the binding sites are further separated. The present findings indicate that acetyl- and succinyl-Con A can not be used as mere "divalent" derivatives of the lectin in studies of cell membranes which possess Man7-Man9 oligomannose-type carbohydrates.

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