Chemistry Reference
In-Depth Information
Fig. 7.6
Typical ground state configurations with energy of
21 of the 48mer attached to a surface
of infinite strength. The hydrophobic core is broken into two pieces in this case. The
black and gray
beads
represent the polar and the hydrophobic residues, respectively, the
white beads
represent the
surface. The size of the beads is merely for visualization purpose without correspondence to the
real size of the residues. Graphic is created by VMD [
52
]
−
0.8
3D free space
with an infinite surface field
0.6
0.4
0.2
0
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Temperature, T
Fig. 7.7
Specific heat,
C
V
N
, of the 48mer with (i) no surface fields (
circles
), and (ii) a surface
field with an infinite strength (
triangles
). Statistical errors were calculated from 10 independent
runs. Error bars are shown only if the errors are larger than the size of the points. Without a surface,
the sequence acquires the ground state in a two-step process as indicated by the peak and the weak
shoulder in the specific heat. With a surface of infinite strength, the sequence undergoes transition
in a one-step process in which a single peak is shown in the specific heat
/
The specific heat is a crucial key to reveal the phase transition behaviors. Pioneer-
ing work by Bachmann et al. studied the interactions of the 3D103 sequence with
the three different surfaces of finite strength using the MCCG algorithm [
53
]. They
have identified five conformational pseudophases which are separated by the peaks
in the specific heat at a given value of
HH
. (The term “solubility” s is used in [
53
]
for the same quantity.) As
HH
varies, peaks in the specific heat join together to form
“ridges,” which give the pseudophase transition lines. Depending on the structures
and the degree of adhesion to the substrate, the pseudophases are classified into the
