First time at Proteopedia? Click on the green links, they change the 3D image. Proteopedia is a 3D, interactive encyclopedia of proteins, RNA, DNA and other molecules. With a free user account, you can edit pages in Proteopedia. Visit the Main Page to learn more. Enter the Page of the Year Competition to win a 32GB iPod Touch and other prizes!
Non-Standard Residue
From Proteopedia
Any residue of protein or nucleic acid that is not included in the list of Standard Residues is considered Non-Standard. The atomic coordinates for atoms in non-standard residues are given in records of type HETATM in the PDB file format.
Examples:
Although phosphoserine and phosphothreonine are given as non-standard residues SEP and TPO in 1bkx, and alternative convention may also be followed. For example, phosophserine and phosphothreonine in 1apm are given as standard residues SER and THR in ATOM records plus PO3 groups in HETATM records.
The former scheme of designating modified standard nucleotides with plus signs (+A, +C, +G, +I, +T, +U) was discontinued in the PDB remediation project, effective August 1, 2007.
