Chemistry Reference
In-Depth Information
used in the simulation when the cosolvent and solvent molecules can exchange
with other molecules in the local vicinity of the protein (Kang and Smith 2007).
This is especially true for small systems and/or large values of Γ
23
. In this case
the value of the preferential binding should be adjusted so that
o
NmNN
NN
−
−
3
3
∞
Γ
23
=
−
=
−
NN
N
2
(1.101)
3
31
2
3
1
2
2
o
2
1
1
2
where the zero superscript indicates the total number of molecules in the system.
Hence, as molecules move in or out of the local region the bulk ratio is correspond-
ingly adjusted. This adjustment may appear small but is magnified by the fact that
⟨
N
1
⟩
2
may be very large for biological solutes.
1.4 CONCLUSIONS
In the previous sections, we have attempted to provide a reasonable summary of FST,
including a general derivation, and illustrated a series of known applications of the
theory. In our opinion, the use of FST to analyze experimental and simulation data
represents both the most appropriate approach and also many times the only approach,
for a variety of systems and their properties. The absence of any approximations in
the theory provides a solid theoretical foundation for the analysis of solutions. An
ability to relate these properties to the underlying molecular distributions also ensures
a rigorous link between the atomic and macroscopic picture of solutions.
