A New Cell-Permeable Fluorescent Probe for Zn²⁺

A hexahistidine-Zn 2+ -dye label reveals STIM1 surface exposure

“…Just as tetracysteine sequences and biarsenical dyes have benefited greatly from multiple rounds of improvement (26,27), the His 6 sequence and HisZiFiT should be similarly optimized to provide tighter binding, increased photostability, decreased background staining, and additional wavelengths. Eventually it may become possible to label intracellular histidine-rich sequences, because it should be possible to synthesize membrane-permeant versions of HisZiFiT and Zn 2ϩ can be separately delivered with ionophores (12). Another conceivable application would be to provide a prolonged mark at sites of endogenous Zn 2ϩ release as in glutamatergic synapses or insulin-secreting beta cells.…”

“…1A). Placement of the two pyridylsulfonamides at the 2Ј,7Ј-positions insures that they bind separate Zn 2ϩ ions, whereas 4Ј,5Ј-substituents can jointly coordinate a single Zn 2ϩ ion (12), saturating its coordination capacity and leaving no detectable affinity for oligo-histidine binding. After describing the synthesis, spectra, and binding properties of HisZiFiT and its complexes, we show that it is a useful label for surface-exposed hexahistidinetagged proteins.…”

Development of Bis(2‐picolyl)amine–Zinc Chelates for Imidazole Receptors

“…[12,13] Recently, examples of Dpa-functionalized metal-anion fluorescence probes have been reported in which Dpa units have been linked to a fluorescent host molecule. [13b, [14][15][16] Lately, it has also been demonstrated that bimetallic double Dpa chelates can function in molecular recognition of anionic species, for example, phosphate, [17] pyrophosphate, [18] or phospholipid [19] anions, as well as histidine residues to some extent. [20] We have studied metal-ligand structures that are capable of zinc chelation and usable for anion recognition purposes in biological environments.…”

A novel small molecule fluorescent sensor for Zn2+ based on pyridine–pyridone scaffold

“…We realized that Zn 2+ selective fluorescent probes have mainly used three core structures, namely quinoline, BF 2 chelated dipyrromethene and fluorescein [21][22][23][24][25][26][27][28][29][30]. After modification of the core structure in getting selectivity toward Zn 2+ , the molecule obviously became bigger and more hydrophobic.…”