Competitive protein adsorption on charge regulating silica-like surfaces: the role of protonation equilibrium.

Autor:	Cathcarth M; Instituto de Investigaciones Fisicoquímicas, Teóricas y Aplicadas (INIFTA), UNLP-CONICET, La Plata, Argentina., Picco AS; Instituto de Investigaciones Fisicoquímicas, Teóricas y Aplicadas (INIFTA), UNLP-CONICET, La Plata, Argentina., Mondo GB; Brazilian Synchrotron (LNLS) and Brazilian Nanotechnology Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil.; Institute of Chemistry (IQ), University of Campinas (UNICAMP), Campinas, Brazil., Cardoso MB; Brazilian Synchrotron (LNLS) and Brazilian Nanotechnology Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil.; Institute of Chemistry (IQ), University of Campinas (UNICAMP), Campinas, Brazil., Longo GS; Instituto de Investigaciones Fisicoquímicas, Teóricas y Aplicadas (INIFTA), UNLP-CONICET, La Plata, Argentina.
Jazyk:	angličtina
Zdroj:	Journal of physics. Condensed matter : an Institute of Physics journal [J Phys Condens Matter] 2022 Jul 05; Vol. 34 (36). Date of Electronic Publication: 2022 Jul 05.
DOI:	10.1088/1361-648X/ac6388
Abstrakt:	We develop a molecular thermodynamic theory to study the interaction of some proteins with a charge regulating silica-like surface under a wide range of conditions, including pH, salt concentration and protein concentration. Proteins are modeled using their three dimensional structure from crystallographic data and the average experimental pKa of amino acid residues. As model systems, we study single-protein and binary solutions of cytochrome c, green fluorescent protein, lysozyme and myoglobin. Our results show that protonation equilibrium plays a critical role in the interactions of proteins with these type of surfaces. The terminal hydroxyl groups on the surface display considerable extent of charge regulation; protein residues with titratable side chains increase protonation according to changes in the local environment and the drop in pH near the surface. This behavior defines protein-surface interactions and leads to the emergence of several phenomena: (i) a complex non-ideal surface charge behavior; (ii) a non-monotonic adsorption of proteins as a function of pH; and (iii) the presence of two spatial regions, a protein-rich and a protein-depleted layer, that occur simultaneously at different distances from the surface when pH is slightly above the isoelectric point of the protein. In binary mixtures, protein adsorption and surface-protein interactions cannot be predicted from single-protein solution considerations. (© 2022 IOP Publishing Ltd.)
Databáze:	MEDLINE
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