Effect of polyethylene glycols on the alkaline-induced molten globule intermediate of bovine serum albumin.

Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000, PR China.
International journal of biological macromolecules (Impact Factor: 2.37). 04/2012; 51(1-2):97-104. DOI: 10.1016/j.ijbiomac.2012.04.021
Source: PubMed

ABSTRACT In the present study, the formation of one molten globule-like unfolding intermediate of bovine serum albumin (BSA) at pH 11.2 has been established with the help of circular dichroism (CD) spectra, fluorescence spectroscopy and 'phase diagram' approach. Additionally, we have shown the conformational changes occurring in the pH 11.2 intermediate of BSA when it was exposed to different molecular weight polyethylene glycols (PEGs) at varying concentrations. When the pH 11.2 intermediate of BSA was treated by PEG 400 there was induction of secondary and non-native tertiary contacts. In case of PEG 8000 and PEG 20,000, the loss in secondary as well as tertiary structure was observed. PEG 8000 and 20,000 altered the conformation of the pH 11.2 intermediate and resulted in its transition to another intermediate state in which the hydrophobic patches were inaccessible.

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