Renumbering PDB files

From Proteopedia

Chemical groups (residues) in atomic coordinate files (PDB files) are numbered. For polymers (protein, DNA, RNA), the amino acid and nucleotide groups are given sequence numbers. For non-polymer groups (hetero groups in PDB terminology), the numbers are arbitrary. The wwPDB allows arbitrary numbering of polymer sequences. See examples at Unusual sequence numbering. Discrepancies in numbering are confusing and frustrating when comparing structures of similar macromolecules.

Below are servers that will re-number atomic coordinate files.