Mesoscopic Properties of Molecular Folding and Aggregation Processes

Protein folding, peptide aggregation and crystallization, as well as adsorption of molecules on soft or solid substrates have an essential feature in common: In all these processes, structure formation is guided by a collective, cooperative behavior of the molecular subunits lining up to build chainlike macromolecules. Proteins experience conformational transitions related to thermodynamic phase transitions. For chains of finite length, an important 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 or energetic fluctuations. Nonetheless, in order to understand generic properties of molecular structure-formation processes, the analysis of mesoscopic models from a statistical physics point of view enables first insights into the nature of conformational transitions in small systems. Here, we review recent results obtained by means of sophisticated generalized-ensemble computer simulations of minimalistic coarse-grained models.