Thimerosal changes protein conformation and increase the rate of fibrillation in physiological conditions: Spectroscopic studies using bovine serum albumin (BSA).
Int J Biol Macromol
; 113: 1032-1040, 2018 Jul 01.
Article
em En
| MEDLINE
| ID: mdl-29476861
The interaction between bovine serum albumin (BSA) and thimerosal (TM), an organomercury compound widely employed as a preservative in vaccines, was investigated simulating physiological conditions and using different spectroscopic techniques. The results, employing molecular fluorescence showed the interaction occurs by static quenching through electrostatic forces (ΔHâ¯<â¯0 and ΔSâ¯>â¯0), spontaneously (ΔGâ¯=â¯-4.40â¯kJâ¯mol-1) and with a binding constant of 3.24â¯×â¯103â¯M-1. Three-dimensional fluorescence studies indicated that TM causes structural changes in the polypeptide chain of the BSA, confirmed by circular dichroism that showed an increase in α-helix (from 43.9 to 47.8%) content after interaction process. Through synchronized fluorescence and employing bilirubin as a protein site marker, it was confirmed the preferential interaction of TM in the subdomain IB of BSA. The interaction mechanism proposed in this work is based on the reaction of TM with BSA through of free Cys34 residue, forming the adduct BSA-HgEt with the thiosalicylic acid release, which possibly interacts electrostatically with positive side chain amino acids of the modified protein. Finally, it was proven that both TM and EtHgCl accelerate the protein fibrillation kinetics in 42 and 122%, respectively, indicating the toxicity of these compounds in biological systems.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Timerosal
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Soroalbumina Bovina
/
Multimerização Proteica
Limite:
Animals
Idioma:
En
Revista:
Int J Biol Macromol
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Holanda