Janelia Fluor 549, Azide (JF549, Azide ) is a fluorescent dye with the absorption maximum (λab (max)) of 549 nm and emission maximum (λem (max)) of 571 nm [1]. 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. It contains an azide group and can undergo copper-catalyzed azide-alkyne cycloaddition (CuAAc) with molecules containing alkyne groups. It can also undergo ring strain-promoted alkyne-azide cycloaddition (SPAAC) with molecules containing DBCO or BCN groups.
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.
References:
[1]. Jonathan B Grimm, et al. Synthesis of Janelia Fluor HaloTag and SNAP-Tag Ligands and Their Use in Cellular Imaging Experiments. Methods Mol Biol. 2017;1663:179-188.
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.
References:
[1]. Jonathan B Grimm, et al. Synthesis of Janelia Fluor HaloTag and SNAP-Tag Ligands and Their Use in Cellular Imaging Experiments. Methods Mol Biol. 2017;1663:179-188.