Crowded milieu prevents fibrillation of hen egg white lysozyme with retention of enzymatic activity

• HEWL undergoes fibrillation at alkaline pH via a molten globule state.
• PEG prevents fibrillation of HEWL stabilizing its native state.
• PEG media assists in retaining enzymatic activity of HEWL.
• 20PEG acts as a more efficient crowding agent compared to 35PEG.
• Hydrodynamic radius of PEG plays a critical role.

Molten globule state plays a crucial role in the amyloidogenesis of several proteins. Hen egg white lysozyme (HEWL) acquires a molten globule state at alkaline pH (12.75). Our study reveals a significant inhibitory effect of high molecular weight polyethylene glycols (PEG) (PEG 20000 and PEG 35000) against alkali-salt mediated fibrillation of HEWL. Native state of HEWL is stabilized in the presence of PEGs accompanied by a decrease in the β-sheet content. Enzymatic activity of HEWL is mostly retained in the presence of polyethylene glycols. The comparable hydrodynamic radius (Rh) of PEG 20000 and native HEWL is central reason to the greater inhibitory potency of PEG 20000 against HEWL fibrillation.

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