Amyloid fibril formation by β-lactoglobulin is inhibited by gold nanoparticles

• Colloidal AuNPs prepared by citrate reduction method.
• Heat exposed β-lg itself form amyloid fibrillar aggregates.
• AuNPs has an excellent inhibitory activity of β-lg aggregation.
• AuNPs inhibits formation of higher aggregation of β-lg stabilizing dimeric form.

The endogenous deposition of protein fibrillar aggregates in the tissues is the cause of several neurodisorders. In the present study the native β-lactoglobulin (β-lg) has been driven towards amyloid fibrillar aggregates when it was exposed to heat at 75 °C for 1 h at pH 7.5. The citrate stabilized gold nanoparticle (AuNPs) of 20 nm diameter is shown to inhibit the thermal aggregation of β-lg. The stability of the β-lg against heat stress was assessed by studying its aggregation at 75 °C, either in presence or in absence of AuNPs. AuNPs stabilizes the monomeric and dimeric forms of the β-lg inhibiting the nucleation and elongation for the formation of higher aggregates. Incubation of β-lg with AuNPs at 75 °C results in the formation of smaller ragged aggregates. Results show that AuNPs possess the capability of inhibiting the formation of amyloid fibrillar aggregates of β-lg in a concentration-dependent manner and may thus facilitate the refolding into native like structure. AuNPs thus serve as nano-chaperon to inhibit the protein aggregation. Thus chaperon like activity of AuNP may be exploited in the design of rational therapeutics for the neurodegenerative diseases.

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