Thermodynamics of peptide aggregation processes: an analysis from perspectives of three statistical ensembles.
We employ a mesoscopic model for studying aggregation processes of proteinlike hydrophobic-polar heteropolymers. By means of multicanonical Monte Carlo computer simulations, we find strong indications that peptide aggregation is a phase separation process, in which the microcanonical entropy exhibits a convex intruder due to non-negligible surface effects of the small systems. We analyze thermodynamic properties of the conformational transitions accompanying the aggregation process from the multicanonical, canonical, and microcanonical perspective. It turns out that the microcanonical description is particularly advantageous as it allows for unraveling details of the phase-separation transition in the thermodynamic region, where the temperature is not a suitable external control parameter anymore.
Junghans
Christoph
C
Institut für Theoretische Physik and Centre for Theoretical Sciences NTZ, Universität Leipzig, Postfach 100920, D-04009 Leipzig, Germany. junghans@mpip.mainz.mpg.de
Bachmann
Michael
M
Janke
Wolfhard
W
D003198:Computer Simulation; D019281:Dimerization; D019277:Entropy; D057927:Hydrophobic and Hydrophilic Interactions; D015233:Models, Statistical; D009010:Monte Carlo Method; D010455:Peptides / Q000737:chemistry*; D044367:Phase Transition; D011487:Protein Conformation; D055672:Static Electricity; D013816:Thermodynamics
D010455:Peptides