help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Tang, K. E. S.
Right arrow Articles by Bloomfield, V. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Tang, K. E. S.
Right arrow Articles by Bloomfield, V. A.

Biophys J, June 2002, p. 2876-2891, Vol. 82, No. 6

Assessing Accumulated Solvent Near a Macromolecular Solute by Preferential Interaction Coefficients

Karen E. S. Tang and Victor A. Bloomfield

Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, Minnesota 55108-1022 USA

Biological macromolecules are often studied in mixed solvents. To understand cosolvent-macromolecule interactions, the preferential interaction coefficient, Gamma 3, may help determine surface solvent compositions. Gamma 3 measures the amounts of water, B1, and cosolvent, B3, within the "local domain," the (possibly far-reaching) region surrounding the macromolecule where the solvent is nonbulk-like. The local domain's boundary is, however, vague and it is unclear which molecules are counted in Bi. It is useful to explore a simple model system to make Bi more concrete and to understand which aspects of the surface solvent distribution, rho (x), are sampled by Gamma 3. We performed computer simulations on a two-dimensional (2D) system consisting of a hard-wall solute (the macromolecule) in a mixed solvent (hard disks of different radii). We simultaneously calculated Gamma 3 and rho (x). We found that 1) in practice, the local domain's boundary is demarked by the outer limit of the first cosolvent (not water) layer; Bi mainly counts the solvent near the macromolecule; 2) assuming B1 to count only the waters within the first water layer is a poor approximation; 3) when determining B1 and B3, water and cosolvent molecules must be counted from the same region of space. We speculate that these 2D results may serve as a first-order approximation for the dominant contributions to Gamma 3 even in three dimensions, so long as the cosolvent is not strongly excluded from the macromolecular surface and there is no significant long-ranged solvent structure.

Biophys J, June 2002, p. 2876-2891, Vol. 82, No. 6
© 2002 by the Biophysical Society   0006-3495/02/06/2876/16  $2.00


This article has been cited by other articles:


Home page
 Biophys. JHome page
P. E. Smith
Chemical Potential Derivatives and Preferential Interaction Parameters in Biological Systems from Kirkwood-Buff Theory
Biophys. J., August 1, 2006; 91(3): 849 - 856.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
S. Shimizu
Estimating hydration changes upon biomolecular reactions from osmotic stress, high pressure, and preferential hydration experiments
PNAS, February 3, 2004; 101(5): 1195 - 1199.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
S. Khrapunov and M. Brenowitz
Comparison of the Effect of Water Release on the Interaction of the Saccharomyces cerevisiae TATA Binding Protein (TBP) with "TATA Box" Sequences Composed of Adenosine or Inosine
Biophys. J., January 1, 2004; 86(1): 371 - 383.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2002 by the Biophysical Society.