How are models in NMR ensembles organized in PDB entries?
A. In older NMR files the atom serial numbers were consecutive across all models in the entry. Owing to limitations in the field width for the atom serial number, this practice resulted in some ensembles being divided among multiple PDB entries. With entries processed since February 1999, the atom serial number is reset to 1 at the beginning of each model thereby allowing the full ensemble to be included within a single PDB entry.
