Janelia Fluor® 646, Azide

Janelia Fluor 646, Azide (JF646, Azide ) is a red fluorogenic fluorescent dye containing a click chemistry group Azide. Janelia Fluor 646, Azide can be used for live-cell imaging experiments ^{[1] [2]}. Janelia Fluor fluorescent dyes can be chemically conjugated to the specific HaloTag substrate (a chloroalkane ligand) to form a fluorescent ligand, rather than binding directly to the HaloTag protein itself. Janelia Fluor products are licensed under U.S. Pat. Nos. 9,933,417, 10,018,624 and 10,161,932 and other patents from Howard Hughes Medical Institute. Janelia Fluor 646, Azide is a click chemistry reagent, it contains an Azide group and can undergo copper-catalyzed azide-alkyne cycloaddition reaction (CuAAc) with molecules containing Alkyne groups. It can also undergo strain-promoted alkyne-azide cycloaddition (SPAAC) reactions with molecules containing DBCO or BCN groups (Ex/Em = 646/664 nm).

In Vitro, Janelia Fluor fluorescent dyes do not inherently possess HaloTag-binding activity; however, reactive groups such as azide serve as reaction sites for covalent coupling-via chemical synthesis-to an amino-functionalized HaloTag chloroalkane ligand scaffold, thereby yielding a fluorescent HaloTag ligand. JF646 can serve as a ligand for self-labeling tag (such as HaloTag)^[1]. Janelia Fluor 646, Azide is modified by JF646. JF646, a red fluorescent dye, is photostable, membrane-permeable, has a high extinction coefficient^[2].

References:
[1]. Grimm JB, Muthusamy AK, Liang Y, et al. A general method to fine-tune fluorophores for live-cell and in vivo imaging. Nat Methods. 2017;14(10):987-994. doi:10.1038/nmeth.4403.
[2]. Basu S, et al. FRET-enhanced photostability allows improved single-molecule tracking of proteins and protein complexes in live mammalian cells. Nat Commun. 2018;9(1):2520. Published 2018 Jun 28.