Lactoferrin denaturation induced by anionic surfactants: The role of the ferric ion in the protein stabilization.

Autor: Ferreira GMD; Colloidal and Macromolecular Green Chemistry Group, Department of Chemistry, Federal University of Viçosa, Av. P. H. Rolfs s/n, 36570900 Viçosa, MG, Brazil., Ferreira GMD; Colloidal and Macromolecular Green Chemistry Group, Department of Chemistry, Federal University of Viçosa, Av. P. H. Rolfs s/n, 36570900 Viçosa, MG, Brazil; Department of Chemistry, Federal University of Lavras, Campus Universitário, CP 3037, 37200000 Lavras, MG, Brazil., Agudelo ÁJP; Colloidal and Macromolecular Green Chemistry Group, Department of Chemistry, Federal University of Viçosa, Av. P. H. Rolfs s/n, 36570900 Viçosa, MG, Brazil., Hudson EA; Department of Food Technology, Federal University of Viçosa, Av. P. H. Rolfs s/n, 36570900 Viçosa, MG, Brazil., Pires ACDS; Department of Food Technology, Federal University of Viçosa, Av. P. H. Rolfs s/n, 36570900 Viçosa, MG, Brazil., da Silva LHM; Colloidal and Macromolecular Green Chemistry Group, Department of Chemistry, Federal University of Viçosa, Av. P. H. Rolfs s/n, 36570900 Viçosa, MG, Brazil. Electronic address: luhen@ufv.br.
Jazyk: angličtina
Zdroj: International journal of biological macromolecules [Int J Biol Macromol] 2018 Oct 01; Vol. 117, pp. 1039-1049. Date of Electronic Publication: 2018 May 12.
DOI: 10.1016/j.ijbiomac.2018.05.058
Abstrakt: Here, investigation was made of the interaction between lactoferrin (Lf) and the anionic surfactants sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), and sodium decyl sulfate (DSS), using isothermal titration calorimetry, Nano differential scanning calorimetry (NanoDSC), and fluorescence spectroscopy. The Lf-surfactant interaction was enthalpically favorable (the integral enthalpy change ranged from -5.99 kJ mol -1 , for SDS at pH 3.0, to -0.61 kJ mol -1 , for DSS at pH 12.0) and promoted denaturation of the protein. The Lf denaturation efficiency followed the order DSS < SDS < SDBS. The adsorption capacity of the protein with respect to surfactant strongly depended on pH and the surfactant structure, reaching a maximum value of 505 SDBS molecules per gram of Lf at pH 3.0. The different efficiencies of the surfactants in denaturing Lf were attributed to the balance of hydrophobic and electrostatic interactions, which also depended on pH and the surfactant structure, highlighting the SDBS-tryptophan residue specific interaction, where SDBS acted as a quencher of fluorescence. Interestingly, the NanoDSC and fluorescence measurements showed that the ferric ion bound to Lf increased its stability against denaturation induced by the surfactants. The results have important implications for understanding the influence of surfactants on structural changes in metalloproteins.
(Copyright © 2018 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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