The Formation of Amyloid-Like Fibrils of α-Chymotrypsin in Different Aqueous Organic Solvents

Title:The Formation of Amyloid-Like Fibrils of α-Chymotrypsin in Different Aqueous Organic Solvents

Volume: 19 Issue: 5

Author(s): L. Maria Simon, Ilona Laczko, Anett Demcsak, David Toth, Marta Kotorman and Livia Fulop

Affiliation:

Keywords: Amyloid-like fibril, chemical modification, chymotrypsin, cross β-structure, organic solvent

Abstract: The formation of amyloid-like fibrils of α-chymotrypsin was studied in aqueous ethanol, methanol, tertbutanol, dimethylformamide and acetonitrile. Thioflavin T (ThT), Congo red (CR) and 1-anilino-8-naphthalenesulfonic acid (ANS) binding, turbidity, intrinsic fluorescence and far-UV circular dichroism measurements were employed to characterize the amyloid fibril formation. The greatest extent of fibril formation after incubation for 24 h at pH 7.0 and at 24 oC was in ethanol at 55%, in methanol and dimethylformamide (DMF) at 60-70% and in tert-butanol at 60-80%. The ANS binding and intrinsic fluorescence results showed that the hydrophobic residues are more solvent-exposed in the aggregated form of α-chymotrypsin. The ThT, CR binding and far-UV CD measurements indicated that the formation of the cross-β structure of α-chymotrypsin depends on the polarity of the organic solvent. To determine the role of surface charges in the aggregation, chemically modified forms of α-chymotrypsin were prepared. The citraconylated and succinylated enzymes exhibited a higher and the enzyme forms modified with aliphatic aldehydes a lower propensity for aggregation. These results suggest the important role of surface charges in the aggregation of α-chymotrypsin.

Cite this article as:

Maria Simon L., Laczko Ilona, Demcsak Anett, Toth David, Kotorman Marta and Fulop Livia, The Formation of Amyloid-Like Fibrils of α-Chymotrypsin in Different Aqueous Organic Solvents, Protein & Peptide Letters 2012; 19 (5) . https://dx.doi.org/10.2174/092986612800191071