Modulation of bovine serum albumin fibrillation by ester bonded and conventional gemini surfactants

Abstract

Protein fibrillation has been associated with various neurological disorders. Knowledge about molecular mechanisms of protein aggregation modulators is potentially helpful for therapeutic purposes. In order to find out the key strategies for promotion and inhibition of protein fibrillation and to create better functional designs, we have studied the effect of gemini surfactants on the bovine serum albumin fibrillation. The ThT fluorescence emission spectrum indicates disintegration of BSA fibrils in presence of m-C2-m gemini surfactants (conventional). However, enhancement in BSA fibril formation takes place in presence of m-E2-m diester bonded gemini surfactants. Although, with increase in tail length of m-E2-m gemini surfactant, slight disintegration of fibrils also occurs. Circular dichroism data suggest decrease in the β-content of the BSA fibrils in presence of m-C2-m surfactant, while as increase in β-content of fibrils in presence of m-E2-m surfactant. FTIR, TEM, and confocal microscopic results also show that m-C2-m disintegrates and m-E2-m prompts the fibrillation. The electrostatic/hydrogen bonding/hydrophobic balance play important roles in determining the BSA fibrillation and disintegration. Micelles of m-C2-m surfactants disrupt the hydrogen bonding in between the β-strands, hence result in fragmented fibrils. Presence of diester group in m-E2-m surfactant forms hydrogen bonds in between the β-strands resulting in enhancement of fibril formation.