We apologize for Proteopedia being slow to respond. For the past two years, a new implementation of Proteopedia has been being built. Soon, it will replace this 18-year old system. All existing content will be moved to the new system at a date that will be announced here.
Non-Standard Residue
From Proteopedia
Any residue not included in the list of Standard amino acids and nucleotides is considered Non-Standard.
Standard residues (standard amino acids and nucleotides) are defined in the [Protein Data Bank file format (PDB format)] (which was updated on August 1, 2007), and have record type ATOM in PDB-format atomic coordinate files. Standard residues are:
