Figure 1

PDB complexes and interfaces definition. (A) Example of a structure whose asymmetric unit contained half of the known biological unit (left). For each entry of this type, the complete biological unit was obtained from the specialized ftp site of PDB at ftp://ftp.wwpdb.org. (B) Each entry of the database consists of a single and independent protein-DNA interface, which is isolated from the whole PDB complex. Here, two examples that illustrate this feature are shown. (Top) 1am9, which PDB file contains two separable complexes, each having a single protein-DNA interface; (Bottom) 1h89, which has one complex, but with two independent protein-DNA interfaces. Each interface has assigned a unique ID in the database.