Biophysical evaluation of amyloid fibril formation in bovine cytochrome c by sodium lauroyl sarcosinate (sarkosyl) in acidic conditions

Surfactant-induced amyloid fibril formation in protein has a lot of association in the laboratory and industrial application. Sodium lauroyl sarcosinate (sarkosyl) is used to solubilize protein aggregates during protein purification, however, its amyloid fibril induction properties are very less understood. The aim of the current work is to examine the role of sarkosyl on the amyloid fibrillation of bovine cytochrome c protein at pH 3.5. We have used various spectroscopic (turbidity, RLS, ThT and far-UV CD) and microscopic (TEM) techniques to characterize the fibrillation of cytochrome c at low pH. We have demonstrated that sarkosyl in the concentrations range 0.5 to 10.0 mM is inducing large size aggregates in cytochrome c with fibrillar morphology. At concentrations of ≤ 0.5 mM, sarkosyl was not able to induce amyloid-like aggregates in cytochrome c at the same pH. The α-helical content of cytochrome c is transformed into β-sheet structure (single minima at 218 nm) in the presence of ≥ 0.5 mM of sarkosyl. The amyloid fibril formation potency is dependent on the concentrations of sarkosyl and solution pH. We believe the results of this work will not only help to explain the molecular mechanism of amyloid fibril formation, but also give us an insight on rationally designing potential anti-amyloidogenic molecules.