Mesoscopic Properties of Molecular Folding and Aggregation Processes

Protein folding, peptide aggregation and crystallization, as well asadsorption of molecules on soft or solid substrates have an essential featurein common: In all these processes, structure formation is guided by acollective, cooperative behavior of the molecular subunits lining up to buildchainlike macromolecules. Proteins experience conformational transitionsrelated to thermodynamic phase transitions. For chains of finite length, animportant difference of crossovers between conformational (pseudo)phases is,however, that these transitions are typically rather smooth processes, i.e.,thermodynamic activity is not necessarily signalized by strong entropic orenergetic fluctuations. Nonetheless, in order to understand generic propertiesof molecular structure-formation processes, the analysis of mesoscopic modelsfrom a statistical physics point of view enables first insights into the natureof conformational transitions in small systems. Here, we review recent resultsobtained by means of sophisticated generalized-ensemble computer simulations ofminimalistic coarse-grained models.