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 applied in excess. That means each time when a Strep-Tactin:desthiobiotin complex dissociates on the column, the resulting free Strep-Tactin binding site may be occupied by HABA or desthiobiotin in competition. As HABA is applied in excess, desthiobiotin has only a reduced chance to find a free binding pocket, which finally results in accelerated removal of desthiobiotin from the column.
