Alginate Trisaccharide Binding Sites on the Surfaceof β-Lactoglobulin Identified by NMR Spectroscopy: Implications for Molecular Network Formation

Emil G. P. Stender, Johnny Birch, Christian Kjeldsen, Lau D. Nielsen, Jens Ø. Duus, Birthe B. Kragelund, Birte Svensson*

*Corresponding author for this work

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Abstract

β-lactoglobulin (BLG) is apromiscuous protein in terms of ligand interactions, having several binding sites reported for hydrophobic biomolecules such as fatty acids, lipids, and vitamins as well as detergents. BLG also interacts with neutral and an ionic oligo- and polysaccharides for which the binding sites remain to be identified. The multivalency offered by these carbohydrate ligands is expected to facilitate coacervation, an electrostatically driven liquid–liquid phase separation. Using heteronuclear single quantum coherence NMR spectroscopy and monitoring chemical shift perturbations, we observed specific binding sites of modest affinity for alginate oligosaccharides (AOSs) prepared by alginate lyase degradation. Two different AOS binding sites (site 1 and site 2) centered around K75 and K101 were identified for monomeric BLG isoform A (BLGA) at pH 2.65. In contrast, only site1 around K75 was observed for dimeric BLGA at pH 4.0. The data suggesta pH-dependent mechanism whereby both the BLGA dimer–monomer equilibrium and electrostatic interactions are exploited. This variability allows for control of coacervation and particle formation of BLGA/alginate mixtures via directed polysaccharide bridging of AOS binding sites and has implication for molecular network formation. The results are valuable for design of polyelectrolyte-based BLG particles and coacervates for carrying nutraceuticals and modulating viscosity in dairy products by use of alginates.
Original languageEnglish
JournalACS Omega
Volume4
Issue number4
Pages (from-to)6165-6174
Number of pages10
DOIs
Publication statusPublished - 2019

Bibliographical note

ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.

Cite this

@article{413ab15d625347f4a2539194faaffa89,
title = "Alginate Trisaccharide Binding Sites on the Surfaceof β-Lactoglobulin Identified by NMR Spectroscopy: Implications for Molecular Network Formation",
abstract = "β-lactoglobulin (BLG) is apromiscuous protein in terms of ligand interactions, having several binding sites reported for hydrophobic biomolecules such as fatty acids, lipids, and vitamins as well as detergents. BLG also interacts with neutral and an ionic oligo- and polysaccharides for which the binding sites remain to be identified. The multivalency offered by these carbohydrate ligands is expected to facilitate coacervation, an electrostatically driven liquid–liquid phase separation. Using heteronuclear single quantum coherence NMR spectroscopy and monitoring chemical shift perturbations, we observed specific binding sites of modest affinity for alginate oligosaccharides (AOSs) prepared by alginate lyase degradation. Two different AOS binding sites (site 1 and site 2) centered around K75 and K101 were identified for monomeric BLG isoform A (BLGA) at pH 2.65. In contrast, only site1 around K75 was observed for dimeric BLGA at pH 4.0. The data suggesta pH-dependent mechanism whereby both the BLGA dimer–monomer equilibrium and electrostatic interactions are exploited. This variability allows for control of coacervation and particle formation of BLGA/alginate mixtures via directed polysaccharide bridging of AOS binding sites and has implication for molecular network formation. The results are valuable for design of polyelectrolyte-based BLG particles and coacervates for carrying nutraceuticals and modulating viscosity in dairy products by use of alginates.",
author = "Stender, {Emil G. P.} and Johnny Birch and Christian Kjeldsen and Nielsen, {Lau D.} and Duus, {Jens {\O}.} and Kragelund, {Birthe B.} and Birte Svensson",
note = "ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.",
year = "2019",
doi = "10.1021/acsomega.8b03532",
language = "English",
volume = "4",
pages = "6165--6174",
journal = "ACS Omega",
issn = "2470-1343",
publisher = "ACS Publications",
number = "4",

}

Alginate Trisaccharide Binding Sites on the Surfaceof β-Lactoglobulin Identified by NMR Spectroscopy: Implications for Molecular Network Formation. / Stender, Emil G. P.; Birch, Johnny; Kjeldsen, Christian; Nielsen, Lau D.; Duus, Jens Ø.; Kragelund, Birthe B.; Svensson, Birte.

In: ACS Omega, Vol. 4, No. 4, 2019, p. 6165-6174.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Alginate Trisaccharide Binding Sites on the Surfaceof β-Lactoglobulin Identified by NMR Spectroscopy: Implications for Molecular Network Formation

AU - Stender, Emil G. P.

AU - Birch, Johnny

AU - Kjeldsen, Christian

AU - Nielsen, Lau D.

AU - Duus, Jens Ø.

AU - Kragelund, Birthe B.

AU - Svensson, Birte

N1 - ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.

PY - 2019

Y1 - 2019

N2 - β-lactoglobulin (BLG) is apromiscuous protein in terms of ligand interactions, having several binding sites reported for hydrophobic biomolecules such as fatty acids, lipids, and vitamins as well as detergents. BLG also interacts with neutral and an ionic oligo- and polysaccharides for which the binding sites remain to be identified. The multivalency offered by these carbohydrate ligands is expected to facilitate coacervation, an electrostatically driven liquid–liquid phase separation. Using heteronuclear single quantum coherence NMR spectroscopy and monitoring chemical shift perturbations, we observed specific binding sites of modest affinity for alginate oligosaccharides (AOSs) prepared by alginate lyase degradation. Two different AOS binding sites (site 1 and site 2) centered around K75 and K101 were identified for monomeric BLG isoform A (BLGA) at pH 2.65. In contrast, only site1 around K75 was observed for dimeric BLGA at pH 4.0. The data suggesta pH-dependent mechanism whereby both the BLGA dimer–monomer equilibrium and electrostatic interactions are exploited. This variability allows for control of coacervation and particle formation of BLGA/alginate mixtures via directed polysaccharide bridging of AOS binding sites and has implication for molecular network formation. The results are valuable for design of polyelectrolyte-based BLG particles and coacervates for carrying nutraceuticals and modulating viscosity in dairy products by use of alginates.

AB - β-lactoglobulin (BLG) is apromiscuous protein in terms of ligand interactions, having several binding sites reported for hydrophobic biomolecules such as fatty acids, lipids, and vitamins as well as detergents. BLG also interacts with neutral and an ionic oligo- and polysaccharides for which the binding sites remain to be identified. The multivalency offered by these carbohydrate ligands is expected to facilitate coacervation, an electrostatically driven liquid–liquid phase separation. Using heteronuclear single quantum coherence NMR spectroscopy and monitoring chemical shift perturbations, we observed specific binding sites of modest affinity for alginate oligosaccharides (AOSs) prepared by alginate lyase degradation. Two different AOS binding sites (site 1 and site 2) centered around K75 and K101 were identified for monomeric BLG isoform A (BLGA) at pH 2.65. In contrast, only site1 around K75 was observed for dimeric BLGA at pH 4.0. The data suggesta pH-dependent mechanism whereby both the BLGA dimer–monomer equilibrium and electrostatic interactions are exploited. This variability allows for control of coacervation and particle formation of BLGA/alginate mixtures via directed polysaccharide bridging of AOS binding sites and has implication for molecular network formation. The results are valuable for design of polyelectrolyte-based BLG particles and coacervates for carrying nutraceuticals and modulating viscosity in dairy products by use of alginates.

U2 - 10.1021/acsomega.8b03532

DO - 10.1021/acsomega.8b03532

M3 - Journal article

VL - 4

SP - 6165

EP - 6174

JO - ACS Omega

JF - ACS Omega

SN - 2470-1343

IS - 4

ER -