The concept is most commonly applied to biological macromolecules such as proteins and RNA, but also be used for polysaccharides and other molecules.
In proteins, backbone dihedral angles and side chain rotamers are commonly used as parameters, and in RNA the base pairing pattern may be used.
These characteristics are used to define the degrees of freedom (in the statistical mechanics sense of a possible "microstate").
The entropy of heterogeneous random coil or denatured proteins is significantly higher than that of the tertiary structure of its folded native state.
Side-chain conformational entropies can be defined as Boltzmann sampling over all possible rotameric states:[3] where R is the gas constant and pi is the probability of a residue being in rotamer i.