Electrostatically Driven Protein Adsorption: Charge Patches versus Charge Regulation

The mechanisms of electrostatically driven adsorption of proteins on charged surfaces are studied with a new theoretical framework. The acid-base behavior, charge distribution, and electrostatic contributions to the thermodynamic properties of the proteins are modeled in the presence of a charged su...

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Detalles Bibliográficos
Autores principales: Boubeta, F.M., Soler-Illia, G.J.A.A., Tagliazucchi, M.
Formato: JOUR
Materias:
Adsorption
Amino acids
Charged particles
Electrostatics
Ionic strength
Thermodynamic properties
Adsorption of proteins
Charged amino acids
Electrostatic contributions
Electrostatically driven
High ionic strength
Iso-electric points
Protein orientation
Theoretical framework
Proteins
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_07437463_v34_n51_p15727_Boubeta
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_07437463_v34_n51_p15727_Boubeta
record_format dspace
spelling todo:paper_07437463_v34_n51_p15727_Boubeta2023-10-03T15:38:50Z Electrostatically Driven Protein Adsorption: Charge Patches versus Charge Regulation Boubeta, F.M. Soler-Illia, G.J.A.A. Tagliazucchi, M. Adsorption Amino acids Charged particles Electrostatics Ionic strength Thermodynamic properties Adsorption of proteins Charged amino acids Electrostatic contributions Electrostatically driven High ionic strength Iso-electric points Protein orientation Theoretical framework Proteins The mechanisms of electrostatically driven adsorption of proteins on charged surfaces are studied with a new theoretical framework. The acid-base behavior, charge distribution, and electrostatic contributions to the thermodynamic properties of the proteins are modeled in the presence of a charged surface. The method is validated against experimental titration curves and apparent pKas. The theory predicts that electrostatic interactions favor the adsorption of proteins at their isoelectric points on charged surfaces despite the fact that the protein has no net charge in solution. Two known mechanisms explain adsorption under these conditions: (i) charge regulation (the charge of the protein changes due to the presence of the surface) and (ii) charge patches (the protein orients to place charged amino acids near opposite surface charges). This work shows that both mechanisms contribute to adsorption at low ionic strengths, whereas only the charge-patch mechanism operates at high ionic strength. Interestingly, the contribution of charge regulation is insensitive to protein orientation under all conditions, which validates the use of constant-charge simulations to determine the most stable orientation of adsorbed proteins. The present study also shows that the charged surface can induce large shifts in the apparent pKas of individual amino acids in adsorbed proteins. Our conclusions are valid for all proteins studied in this work (lysozyme, α-amylase, ribonuclease A, and β-lactoglobulin), as well as for proteins that are not isoelectric but have instead a net charge in solution of the same sign as the surface charge, i.e. the problem of protein adsorption on the "wrong side" of the isoelectric point. © 2018 American Chemical Society. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_07437463_v34_n51_p15727_Boubeta
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Adsorption
Amino acids
Charged particles
Electrostatics
Ionic strength
Thermodynamic properties
Adsorption of proteins
Charged amino acids
Electrostatic contributions
Electrostatically driven
High ionic strength
Iso-electric points
Protein orientation
Theoretical framework
Proteins
spellingShingle Adsorption
Amino acids
Charged particles
Electrostatics
Ionic strength
Thermodynamic properties
Adsorption of proteins
Charged amino acids
Electrostatic contributions
Electrostatically driven
High ionic strength
Iso-electric points
Protein orientation
Theoretical framework
Proteins
Boubeta, F.M.
Soler-Illia, G.J.A.A.
Tagliazucchi, M.
Electrostatically Driven Protein Adsorption: Charge Patches versus Charge Regulation
topic_facet Adsorption
Amino acids
Charged particles
Electrostatics
Ionic strength
Thermodynamic properties
Adsorption of proteins
Charged amino acids
Electrostatic contributions
Electrostatically driven
High ionic strength
Iso-electric points
Protein orientation
Theoretical framework
Proteins
description The mechanisms of electrostatically driven adsorption of proteins on charged surfaces are studied with a new theoretical framework. The acid-base behavior, charge distribution, and electrostatic contributions to the thermodynamic properties of the proteins are modeled in the presence of a charged surface. The method is validated against experimental titration curves and apparent pKas. The theory predicts that electrostatic interactions favor the adsorption of proteins at their isoelectric points on charged surfaces despite the fact that the protein has no net charge in solution. Two known mechanisms explain adsorption under these conditions: (i) charge regulation (the charge of the protein changes due to the presence of the surface) and (ii) charge patches (the protein orients to place charged amino acids near opposite surface charges). This work shows that both mechanisms contribute to adsorption at low ionic strengths, whereas only the charge-patch mechanism operates at high ionic strength. Interestingly, the contribution of charge regulation is insensitive to protein orientation under all conditions, which validates the use of constant-charge simulations to determine the most stable orientation of adsorbed proteins. The present study also shows that the charged surface can induce large shifts in the apparent pKas of individual amino acids in adsorbed proteins. Our conclusions are valid for all proteins studied in this work (lysozyme, α-amylase, ribonuclease A, and β-lactoglobulin), as well as for proteins that are not isoelectric but have instead a net charge in solution of the same sign as the surface charge, i.e. the problem of protein adsorption on the "wrong side" of the isoelectric point. © 2018 American Chemical Society.
format JOUR
author Boubeta, F.M.
Soler-Illia, G.J.A.A.
Tagliazucchi, M.
author_facet Boubeta, F.M.
Soler-Illia, G.J.A.A.
Tagliazucchi, M.
author_sort Boubeta, F.M.
title Electrostatically Driven Protein Adsorption: Charge Patches versus Charge Regulation
title_short Electrostatically Driven Protein Adsorption: Charge Patches versus Charge Regulation
title_full Electrostatically Driven Protein Adsorption: Charge Patches versus Charge Regulation
title_fullStr Electrostatically Driven Protein Adsorption: Charge Patches versus Charge Regulation
title_full_unstemmed Electrostatically Driven Protein Adsorption: Charge Patches versus Charge Regulation
title_sort electrostatically driven protein adsorption: charge patches versus charge regulation
url http://hdl.handle.net/20.500.12110/paper_07437463_v34_n51_p15727_Boubeta
work_keys_str_mv AT boubetafm electrostaticallydrivenproteinadsorptionchargepatchesversuschargeregulation
AT solerilliagjaa electrostaticallydrivenproteinadsorptionchargepatchesversuschargeregulation
AT tagliazucchim electrostaticallydrivenproteinadsorptionchargepatchesversuschargeregulation
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