Aggregation behavior of bovine κ- and β-casein studied with small angle neutron scattering, light scattering, and cryogenic transmission electron microscopy

Ossowski, S., Jackson, A., Obiols-Rabasa, M., Holt, C. , Lenton, S., Porcar, L., Paulsson, M. and Nylander, T. (2012) Aggregation behavior of bovine κ- and β-casein studied with small angle neutron scattering, light scattering, and cryogenic transmission electron microscopy. Langmuir, 28(38), pp. 13577-13589. (doi: 10.1021/la302416p)

Abstract

In the native bovine casein micelle the calcium sensitive caseins (αS1-, αS2- and β-casein) sequester amorphous calcium phosphate in nanometer-sized clusters, whereas the calcium-insensitive κ-casein limits the growth of the micelle. In this paper, we further investigate the self-association of κ- and β-casein, which are two of the key proteins that control the substructure of the milk casein micelle, using neutron and light scattering techniques and cryogenic transmission electron microscopy. Results demonstrate that κ-casein can, apart from the known self-assembly, form amyloid-like fibrils already at temperatures of 25 °C when subject to agitation. This extended aggregation behavior of κ-casein is inhibited by β-casein, as reported by others. These findings have implications for the structure and stability of casein micelles. The neutron scattering data was used to gain information on the self-assembly structure of κ-casein. β-Casein shows similar self-association behavior as κ-casein, but unlike κ-casein, the self-association exhibits temperature dependence within the studied temperatures (6 and 25 °C). Here, we will discuss our extended study of the known self-assembly of casein in the context of the fibrillation of κ-casein.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Holt, Dr Carl
• Authors: Ossowski, S., Jackson, A., Obiols-Rabasa, M., Holt, C., Lenton, S., Porcar, L., Paulsson, M., and Nylander, T.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Langmuir
• ISSN: 0743-7463
• Published Online: 27 August 2012