Fig. 1: Chemical structures of the multivalent chelator probes trisNTA and hexaNTA.
From: Ultrafast in-gel detection by fluorescent super-chelator probes with HisQuick-PAGE
The interaction towards His-tagged proteins is based on an octahedral complex of the NTA moiety and the ligand histidine side chains (X) chelating a Ni(II) ion. Due to six individual complex formations, a single super-chelator hexaNTA probe forms kinetically highly stable interactions. As probes for in-gel protein detection during HisQuick-PAGE, the multivalent chelators are covalently coupled to the fluorophore Alexa647 via a carboxy (trisNTA) or thiol modification (hexaNTA).
