How can the Strep-Tactin® matrix be regenerated?
If desthiobiotin is used for elution, the Strep-Tactin® matrix can be regenerated with an azo dye (HABA) which, when applied in excess, displaces desthiobiotin. The dye is yellow in solution and shifts to red when bound by Strep-Tactin which allows the visual control of the regeneration process and the functional status of the column. As long as a colour gradient between the top and the bottom of the column is visible, it is not fully regenerated. Regeneration is not possible, if biotin has been used for elution (Strep-Tactin Spin Columns, Strep-Well HT Purification Plates, MagStrep (Strep-Tactin coated Magnetic Beads), One-StrEP protein:protein interaction analysis) since biotin binds nearly irreversible to Strep-Tactin. • What is the mechanism for HABA displacing desthiobiotin from the Strep-Tactin® column? HABA binds to the same Strep-Tactin binding pocket as Strep-tag (or biotin) does, but with very low affinity only. Nevertheless, it accelerates desthiobiotin removal because it is
