Jump to main content
Jump to site search

Issue 14, 2017
Previous Article Next Article

Sugar-coated proteins: the importance of degree of polymerisation of oligo-galacturonic acid on protein binding and aggregation

Author affiliations

Abstract

We have simplified the structural heterogeneity of protein–polysaccharide binding by investigating protein binding to oligosaccharides. The interactions between bovine beta-lactoglobulin A (βLgA) and oligo-galacturonic acids (OGAs) with various numbers of sugar residues have been investigated with a range of biophysical techniques. We show that the βLgA–OGA interaction is critically dependent on the length of the oligosaccharide. Isothermal titration calorimetry results suggest that a minimum length of 7 or 8 sugar residues is required in order to exhibit appreciable exothermic interactions with βLgA – shorter oligosaccharides show no enthalpic interactions at any concentration ratio. When titrating βLgA into OGAs with more than 7–8 sugar residues the sample solution also became turbid with increasing amounts of βLgA, indicating the formation of macroscopic assemblies. Circular dichroism, thioflavin T fluorescence and small angle X-ray/neutron scattering experiments revealed two structural regimes during the titration. When OGAs were in excess, βLgA formed discrete assemblies upon OGA binding, and no subsequent aggregation was observed. However, when βLgA was present in excess, multi-scale structures were formed and this eventually led to the separation of the solution into two liquid-phases.

Graphical abstract: Sugar-coated proteins: the importance of degree of polymerisation of oligo-galacturonic acid on protein binding and aggregation

Back to tab navigation
Please wait while Download options loads

Publication details

The article was received on 25 Nov 2016, accepted on 13 Mar 2017 and first published on 14 Mar 2017


Article type: Paper
DOI: 10.1039/C6SM02660E
Citation: Soft Matter, 2017,13, 2698-2707
  •   Request permissions

    Sugar-coated proteins: the importance of degree of polymerisation of oligo-galacturonic acid on protein binding and aggregation

    A. Y. Xu, L. D. Melton, T. M. Ryan, J. P. Mata, G. B. Jameson, A. Rekas, M. A. K. Williams and D. J. McGillivray, Soft Matter, 2017, 13, 2698
    DOI: 10.1039/C6SM02660E

Search articles by author