Download MendeleyRevealing the Dimeric Crystal and Solution Structure of beta-Lactoglobulin at pH 4 and Its pH and Salt Dependent Monomer-Dimer Equilibrium.
Khan, S., Ipsen, R., Almdal, K., Svensson, B., Harris, P.(2018) Biomacromolecules 19: 2905-2912
- PubMed: 29737841
- DOI: https://doi.org/10.1021/acs.biomac.8b00471
- Primary Citation of Related Structures:
6FXB - PubMed Abstract:
The dimeric structure of bovine β-lactoglobulin A (BLGA) at pH 4.0 was solved to 2.0 Å resolution. Fitting the BLGA pH 4.0 structure to SAXS data at low ionic strength (goodness of fit R-factor = 3.6%) verified the dimeric state in solution. Analysis of the monomer-dimer equilibrium at varying pH and ionic strength by SAXS and scattering modeling showed that BLGA is dimeric at pH 3.0 and 4.0, shifting toward a monomer at pH 2.2, 2.6, and 7.0 yielding monomer/dimer ratios of 80/20%, 50/50%, and 25/75%, respectively. BLGA remained a dimer at pH 3.0 and 4.0 in 50-150 mM NaCl, whereas the electrostatic shielding raised the dimer content at pH 2.2, 2.6, and 7.0, i.e., below and above the pI. Overall, the findings provide new insights into the molecular characteristics of BLGA relevant for dairy product formulations and for various biotechnological and pharmaceutical applications.
Organizational Affiliation:
Enzyme and Protein Chemistry, Department of Biotechnology and Biomedicine , Technical University of Denmark , Søltofts Plads, Building 224 , DK-2800 Kgs. Lyngby , Denmark.
