ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Study of reactive dye/serum albumin interactions: thermodynamic parameters, protein alterations and computational analysis

Thaís Meira Menezes, Marcos Gomes Ghislandi, Antônio Marinho da Silva Neto, Alcides Jairon Lacerda Cintra, Priscila Gubert, and Jorge Luiz Neves

Departamento de Química Fundamental, Universidade Federal de Pernambuco (UFPE), Recife, Brazil

E-mail: thais.meira@ufrpe.br

Received: 10 August 2022  Accepted: 20 October 2022

Abstract:

Dyes like Reactive Red 241 (DR) are a class of compounds extensively used in the textile industry and are potentially dangerous to the environment and human health. Therefore, understanding the binding characteristics of such substances and biological macromolecules is essential from a toxico-kinetic perspective. The molecular interaction between DR and human serum albumin (HSA) was investigated through spectroscopic techniques and molecular docking approaches. The results indicate that DR quenches HSA fluorescence following a static mechanism, resulting in the HSA–DR complex formation with a moderate interaction (inferred by the binding constant range of 10⁵ M⁻¹). Moreover, the predominant interactions in the HSA–DR system are electrostatic since the measured thermodynamic parameters ΔS° > 0 and ΔH° < 0. FRET results show DR is 5.52 nm distant from fluorophore residue Trp-214, and the interaction is mainly related to Tyr residues. The Ellman assay identified a decrease in the content of HSA free thiol. The results of the RLS suggest damage to the conformation of the protein. Molecular docking suggests the binding site of DR was located in subdomain IIB HSA, corroborating the experimental properties. Finally, the results suggest a high potential for DR toxicity triggered by contact with key proteins, affecting the biomolecule functionalities.

Keywords: Reactive Red 241; Human serum albumin; Fluorescence quenching; Interactions; Molecular docking

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02561-x

Chemical Papers 77 (3) 1519–1532 (2023)