The green boxes represent existing external repositories that provide information referenced from the IHM Dictionary. Macromolecular sequence information is available from UniProt (The UniProt Consortium, 2017) and the International Nucleotide Sequence Database Collaboration (INSDC) (Nakamura et al., 2013); small-molecule chemical information is available from the Cambridge Crystallographic Data Center (CCDC) (Groom et al., 2016); macromolecular structures are archived in the PDB (wwPDB consortium, 2019), ModelArchive (www.modelarchive.org), and PDB-Dev (Burley et al., 2017; Vallat et al., 2018); and various types of experimental data are available from the PDB (wwPDB consortium, 2019), BMRB (Ulrich et al., 2008), EMDB (Tagari et al., 2002), and SASBDB (Valentini et al., 2015). The yellow boxes show the information derived from the repositories used in integrative modeling. The chemistry of the molecular components is already contained in the PDBx/mmCIF dictionary. The starting structural models derived from the structural data repositories and the spatial restraints derived from experimental methods are described in the IHM Dictionary. The orange box depicts the combination of multi-scale, multi-state, ordered ensembles whose representations are defined in the IHM Dictionary (Vallat et al., 2018).