Find PDB Structures with Protein Purification Tags
Protein tags are peptide sequences attached to proteins for various experimental reasons, particularly for purification. Advanced Search can be used to search for entries with these protein purification tags.
To find these structures, select the Sequence Features > Sequence Motif option and enter an exact sequence or a sequence pattern expressed by regular expression syntax. Regular expressions can be used to define complex sequence patterns.
Entering ^HHHHHH will search for a 6 residue long N-terminal polyhistidine-tag (His6 tag), while a search for HHHHHH will find any sequence with a (His)6 pattern. This query looks at the sequence originally studied, and will find entries where an His6 tag appears completely, in part, or not at all in the coordinates.