Journal
PROCESS BIOCHEMISTRY
Volume 50, Issue 9, Pages 1379-1387Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.procbio.2015.05.018
Keywords
Protein-fatty acid complex; alpha-Lactalbumin; Oleic acid; Binding affinity; HAMLET; SPR; ITC; Molecular interactions
Categories
Funding
- National Research Foundation of Korea (NRF) - Korean Government (MSIP) [2010-0012217]
- National Research Foundation of Korea [2010-0012217] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
Ask authors/readers for more resources
To analyze the trends in molecular interaction between bovine alpha-LA (BLA) and oleic acid, we investigated the effects of pH and protein conformation on oleate binding to BLA and compared the order-ofmagnitude differences in binding behavior. Both isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR) were used. For the ITC experiments, a solution of holo- or apo-BLA was titrated with sodium oleate at pH 4.0 and 10.0 to look for protein surface charge effects. In the SPR experiments, BLA was immobilized on the chip surface and sodium oleate solutions at various pHs (4.0, 5.5, 7.0,8.5 and 10.0) were injected. Binding stoichiometry of ca. 5.2 molecules of oleate per unit molecule of BLA was observed. apo-BLA at a lower pH (lower than the pl of alpha-LA) yielded stronger binding avidity and affinity, which indicated that electrostatic interactions between the basic residues and the negatively charged carboxyl groups may play a major role in the complexation, in addition to hydrophobic interactions. The complexes formed at pH 4.0 and 5.5 were relatively unstable and rapidly dissociated when exposed to pH 7.0. In summary, we propose that the complexation can be regarded as a very weak (or, transient) and multivalent binding, requiring both electrostatic and hydrophobic interactions, probably in series and also in a dynamic equilibrium. (C) 2015 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available