Abstract
Equilibrium and kinetic models for nonspecific adsorption of proteins to planar surfaces are presented. These models allow for the possibility of multiple interconvertible surface conformations of adsorbed protein. Steric repulsion resulting in area exclusion by adsorbed molecules is taken into account by treating the adsorbate as a thermodynamically nonideal two-dimensional fluid. In the equilibrium model, the possibility of attractive interactions between adsorbed molecules is taken into account in a limited fashion by permitting one of the adsorbed species to self-associate. Calculated equilibrium adsorption isotherms exhibit apparent high-affinity and low-affinity binding regions, corresponding respectively to adsorption of ligand at low fractional area occupancy in an energetically favorable side-on conformation and conversion at higher fractional area occupancy of the side-on conformation to an entropically favored end-on conformation. Adsorbate self-association may lead to considerable steepening of the adsorption isotherm, compensating to a variable extent for the broadening effect of steric repulsion. Kinetic calculations suggest that in the absence of attractive interactions between adsorbate molecules, the process of adsorption may be highly "stretched" along the time axis, rendering the attainment of adsorption equilibrium in the context of conventional experiments problematic.
Full Text
The Full Text of this article is available as a PDF (167.3 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chatelier R. C., Minton A. P. Adsorption of globular proteins on locally planar surfaces: models for the effect of excluded surface area and aggregation of adsorbed protein on adsorption equilibria. Biophys J. 1996 Nov;71(5):2367–2374. doi: 10.1016/S0006-3495(96)79430-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heimburg T., Marsh D. Protein surface-distribution and protein-protein interactions in the binding of peripheral proteins to charged lipid membranes. Biophys J. 1995 Feb;68(2):536–546. doi: 10.1016/S0006-3495(95)80215-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hummel J. P., Anderson B. S. Ribonuclease adsorption on glass surfaces. Arch Biochem Biophys. 1965 Dec;112(3):443–447. doi: 10.1016/0003-9861(65)90077-9. [DOI] [PubMed] [Google Scholar]
- Kurrat R, Prenosil JE, Ramsden JJ. Kinetics of Human and Bovine Serum Albumin Adsorption at Silica-Titania Surfaces. J Colloid Interface Sci. 1997 Jan 1;185(1):1–8. doi: 10.1006/jcis.1996.4528. [DOI] [PubMed] [Google Scholar]
- Minton A. P. Confinement as a determinant of macromolecular structure and reactivity. II. Effects of weakly attractive interactions between confined macrosolutes and confining structures. Biophys J. 1995 Apr;68(4):1311–1322. doi: 10.1016/S0006-3495(95)80304-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nygren H. Nonlinear kinetics of ferritin adsorption. Biophys J. 1993 Oct;65(4):1508–1512. doi: 10.1016/S0006-3495(93)81221-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ramsden JJ, Bachmanova GI, Archakov AI. Kinetic evidence for protein clustering at a surface. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 1994 Dec;50(6):5072–5076. doi: 10.1103/physreve.50.5072. [DOI] [PubMed] [Google Scholar]
- Roush D. J., Gill D. S., Willson R. C. Electrostatic potentials and electrostatic interaction energies of rat cytochrome b5 and a simulated anion-exchange adsorbent surface. Biophys J. 1994 May;66(5):1290–1300. doi: 10.1016/S0006-3495(94)80924-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schuck P. Use of surface plasmon resonance to probe the equilibrium and dynamic aspects of interactions between biological macromolecules. Annu Rev Biophys Biomol Struct. 1997;26:541–566. doi: 10.1146/annurev.biophys.26.1.541. [DOI] [PubMed] [Google Scholar]
- Sild V., Ståhlberg J., Pettersson G., Johansson G. Effect of potential binding site overlap to binding of cellulase to cellulose: a two-dimensional simulation. FEBS Lett. 1996 Jan 2;378(1):51–56. doi: 10.1016/0014-5793(95)01420-9. [DOI] [PubMed] [Google Scholar]
- Silhavy T. J., Szmelcman S., Boos W., Schwartz M. On the significance of the retention of ligand by protein. Proc Natl Acad Sci U S A. 1975 Jun;72(6):2120–2124. doi: 10.1073/pnas.72.6.2120. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stenberg M., Nygren H. Computer simulation of surface-induced aggregation of ferritin. Biophys Chem. 1991 Nov;41(2):131–141. doi: 10.1016/0301-4622(91)80013-h. [DOI] [PubMed] [Google Scholar]
- Zimmerman S. B., Minton A. P. Macromolecular crowding: biochemical, biophysical, and physiological consequences. Annu Rev Biophys Biomol Struct. 1993;22:27–65. doi: 10.1146/annurev.bb.22.060193.000331. [DOI] [PubMed] [Google Scholar]