The two rotamer libraries described here were built from an analysis of crystallographic protein structures from the Protein Data Bank (PDB). Only proteins at least 30 amino acids long, having no chain breaks, obtained by X-ray diffraction with a resolution better than 2.5 Angstroms were retained.

In date of november 2003, this resulted in a collection of 2926 protein chains presenting less than 30% sequence identity (489528 amino acids, not considering ALA, GLY and PRO). The libraries store the chi values, and the frequencies of occurrence of each conformation.

Gaussian filters are used to determine rotameric values in a way similar to that described by Lovell et al., Proteins 2000 40:389-408.

The first library is a library built not considering backbone conformation (backbone independent rotamer library).
The second library (backbone dependent rotamer library) is the result of an analysis of side chain conformations in the light of the conformation of the backbone of the 4 residue length peptidic fragment englobing it, caracterized by its structural alphabet (SA) state. and from a better.