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

The formation of amyloid-like fibrils of alpha-chymotrypsin was studied in aqueous ethanol, methanol, tert-butanol, dimethylformamide and acetonitrile. Thioflavin T (ThT), Congo red (CR) and 1-anilino-8-naphthalenesulfonic acid (ANS) binding, turbidity, intrinsic fluorescence and far-UV circular dic...

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Bibliographic Details
Main Authors: Lehoczkiné Simon Mária
Laczkó Ilona
Nagy-Demcsák Anett
Tóth Dávid
Kotormán Márta
Fülöp Lívia
Format: Article
Published: 2012
Series:PROTEIN AND PEPTIDE LETTERS 19 No. 5
doi:10.2174/092986612800191071

mtmt:2015363
Online Access:http://publicatio.bibl.u-szeged.hu/16331
Description
Summary:The formation of amyloid-like fibrils of alpha-chymotrypsin was studied in aqueous ethanol, methanol, tert-butanol, 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 degrees C 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 alpha-chymotrypsin. The ThT, CR binding and far-UV CD measurements indicated that the formation of the cross-beta structure of alpha-chymotrypsin depends on the polarity of the organic solvent. To determine the role of surface charges in the aggregation, chemically modified forms of alpha-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 alpha-chymotrypsin.
Physical Description:544-550
ISSN:0929-8665