Issue 59, 2014

Microscopic and thermodynamic analysis of PEG–β-lactoglobulin interaction

Abstract

We report the binding of milk β-lactoglobulin (β-LG) with PEG-3000, PEG-6000 and methoxypoly(ethylene glycol) anthracene (mPEG-anthracene) in aqueous solution at pH 7.4, using multiple spectroscopic methods, thermodynamic analysis, transmission electron microscopy (TEM) and molecular modeling. Thermodynamic and spectroscopic analysis showed that polymers bind β-LG via van der Waals interactions, hydrogen bonding and hydrophobic interactions, with overall binding constants KPEG-3000–β-LG = 9.2 (±0.9) × 103 M−1, KPEG-6000–β-LG = 9.7 (±0.7) × 103 M−1 and KmPEG-anthracene–β-LG = 5.5 (±0.5) × 104 M−1. The binding affinity was mPEG-anthracene > PEG-6000 > PEG-3000. Transmission electron microscopy analysis showed significant changes in protein morphology as polymer–protein complexation occurred, with a major increase in the diameter of the protein aggregate. Modeling showed several hydrogen bonding systems between PEG and the different amino acid stabilized polymer–β-LG complexes. The free binding energy indicated that the interaction process is spontaneous at room temperature. Furthermore, mPEG-anthracene is a stronger protein binder than PEG-3000 and PEG-6000, due to its major hydrophobic characteristics.

Graphical abstract: Microscopic and thermodynamic analysis of PEG–β-lactoglobulin interaction

Article information

Article type
Paper
Submitted
11 avr. 2014
Accepted
26 juin 2014
First published
26 juin 2014

RSC Adv., 2014,4, 31084-31093

Microscopic and thermodynamic analysis of PEG–β-lactoglobulin interaction

L. Bekale, P. Chanphai, S. Sanyakamdhorn, D. Agudelo and H. A. Tajmir-Riahi, RSC Adv., 2014, 4, 31084 DOI: 10.1039/C4RA03303E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements