Study of the serum albumin-polyethyleneglycol interaction to predict the protein partitioning in aqueous two-phase systems

Polymorphism of human telomeric quadruplex structures

“…It is of note that the concentration used for NMR structure determination is in the 2-3 mM range, more than 40 fold higher than the crowding condition used in CD and fluorescence studies with PEG200 [68]. In addition, molecular crowding agents are not supposed to have specific interactions with the test molecular structures [69,70], whereas PEG has been shown to induce enhanced hydrophobic surface area and hydrophobic interactions with the test molecules [71][72][73][74]. However, it is important to note that while the hybrid-type G-quadruplexes are the predominant structures formed by the human telomeric DNA sequence under aqueous conditions, the small energy barrier of different forms, including the parallel form, can make them readily shifted by different protein and ligand bindings.…”

Purification of α‐toxin from Clostridium perfringens type A in PEG‐phosphate aqueous two‐phase systems: a factorial study

“…21 Farrugia et al also found that PEG induces a displacement of the fluorescent probe ANS from its binding site in human albumin. 22 Grimonprez and Johansson 23 reported high yield values in the presence of PEG, varying with enzyme type. Tubio et al suggested that an increase in chain length might lead to an increase in hydrophobicity, thereby enhancing the activity of hydrophobic enzyme.…”

Evaluation of Driving Forces for Protein Partition in PEG-Salt Aqueous Two- Phase Systems and Optimization by Design of Experiments

“…Thereby, specific interactions with PEG can be neglected and would be only significant for smaller PEG chains [42], as reported by Farruggia et al [43]. On the contrary, α-CT/LYZ are strongly directed into the PEG-rich top phase, mainly due to their lower sizes or MWs (MW (α-CT): 25 kDa and MW (LYZ): 14.4 kDa, Table 6), thus diminishing the influence of the excluded volume effects, and their net positive charges at pH 7 (pI (α-CT): 8.75 and pI (LYZ): 11, Table 6) [42].…”

“…Hence, BSA/OVA are more hydrophilic proteins and prefer a partitioning into the saltrich bottom phase, which is the less hydrophobic one [42]. In contrast, α-CT/LYZ are more hydrophobic proteins according to their larger hydrophobic surfaces, and are preferentially distributed into the PEGrich top phase, which is the most hydrophobic one [43]. Overall, the partitioning behavior of the studied model proteins in different PEGsalt ATPS is generally resulting from coexisting effects related to the physicochemical/surface properties of the proteins and system features, as outlined in the following chapters.…”