Alginate Trisaccharide Binding Sites on the Surface of β-Lactoglobulin Identified by NMR Spectroscopy: Implications for Molecular Network Formation
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Alginate Trisaccharide Binding Sites on the Surface of 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.
I: ACS Omega, Bind 4, Nr. 4, 2019, s. 6165-6174.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Alginate Trisaccharide Binding Sites on the Surface of β-Lactoglobulin Identified by NMR Spectroscopy
T2 - 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
PY - 2019
Y1 - 2019
N2 - β-lactoglobulin (BLG) is a promiscuous 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 anionic 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 site 1 around K75 was observed for dimeric BLGA at pH 4.0. The data suggest a 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 a promiscuous 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 anionic 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 site 1 around K75 was observed for dimeric BLGA at pH 4.0. The data suggest a 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
C2 - 31459761
AN - SCOPUS:85063878199
VL - 4
SP - 6165
EP - 6174
JO - ACS Omega
JF - ACS Omega
SN - 2470-1343
IS - 4
ER -
ID: 217932599