The effects of poly(ethylene glycol) on the solution structure of human serum albumin

Abstract

Protein physical and chemical properties can be altered by polymer interaction. The presence of several high affinity binding sites on human serum albumin (HSA) makes it a possible target for many organic and polymer molecules. This study was designed to examine the interaction of HSA with poly(ethylene glycol) (PEG) in aqueous solution at physiological conditions. Fourier transform infrared, ultraviolet-visible, and CD spectroscopic methods were used to determine the polymer binding mode, the binding constant, and the effects of polymer complexation on protein secondary structure. The spectroscopic results showed that PEG is located along the polypeptide chains through H-bonding interactions with an overall affinity constant of K = 4.12 x 10(5) M(-1). The protein secondary structure showed no alterations at low PEG concentration (0.1 mM), whereas at high polymer content (1 mM), a reduction of alpha-helix from 59 (free HSA) to 53% and an increase of beta-turn from 11 (free HSA) to 22% occurred in the PEG-HSA complexes (infrared data). The CDSSTR program (CD data) also showed no major alterations of the protein secondary structure at low PEG concentrations (0.1 and 0.5 mM), while at high polymer content (1 mM), a major reduction of alpha-helix from 69 (free HSA) to 58% and an increase of beta-turn from 7 (free HSA) to 18% was observed.

Design and fabrication of a food-grade albumin-stabilized nanoemulsion

“…The increase in intensity of amide І and amide ІІ bands are due to PEG binding to protein C]O, CeN and NeH groups. In agreement with previous studies on the interaction of PEG and human serum albumin (HSA) in solution (Ragi, Sedaghat-Herati, Ouameur, & Tajmir-Riahi, 2005;Wu, Wang, Lin, & Chen, 2013), our study found no alteration to BSA secondary structure.…”

Structural intermediates of acid unfolded Con-A in different co-solvents: Fluoroalcohols and polyethylene glycols

“…In another study [12] it was shown that PEG at low concentrations had no effect on the secondary structure while on increasing the concentration a considerable decrease in structure was observed. It has been found that PEGs tend to have different effects on different proteins depending upon their chemical nature.…”

“…Protein physical and chemical properties can also be altered by polymer interaction [12]. The PEG polymers are a series of nonionic polyhydroxyl compounds that are miscible with water and display colligative properties in solution.…”

Amyloid-like Fibril Formation by Trypsin in Aqueous Ethanol. Inhibition of Fibrillation by PEG

“…Recently, some authors have reported on inhibition of fibrillation as well as destabilization of preformed fibrils using polyphenols [13,14]. Polyethylene glycols (PEGs) are nontoxic, biocompatible, water-soluble, hydrophilic non-ionic polymers that can interact with proteins through hydrogenbonding or hydrophobic interactions [15][16][17]. They have potential protective effects on various types of protein denaturation [18].…”