Understanding the applicability and limitations of Wang–Landau method for biomolecules: Met-enkephalin and Trp-cage

Wang–Landau (WL) method is an efficient way to calculate density of states (DOS), thermodynamic and structural properties of a system. In this work, two different flavors of WL method, its original implementation and the t−1 method of Belardinelli et al., are applied to met-enkephalin and Trp-cage to understand their efficacy and limitations. Accurate thermodynamic and structural quantities are calculated for both the peptides considered. For Trp-cage, fragmenting the energy range into different parts and determining DOS for each part is found to be a feasible way to use WL method. The problem of low temperature sampling of WL method is discussed.