HIS Lite(TM) Cy5 Tris NTA Chelator

Correction Factor (260 nm): 0.02. Correction Factor (280 nm): 0.03. Correction Factor (482 nm): 0.009. Correction Factor (565 nm): 0.09. Extinction coefficient (cm^-1 M^-1): 250000 (ethanol). Excitation (nm): 651. Emission (nm): 670. Quantum yield: 0.27 (PBS), 0.4(). Cy5-Tris NTA compound is a sensitive fluorescent chelator for detecting polyhistidine-labeled proteins in cells, solution and solid surfaces with the addition of certain metal ions (such as Ni2+, Co2+ etc.) as a mediator. It is the chelator of our HIS Lite(TM) Cy5 Tris NTA-Ni Complex (#12619). In combination with other color tris-NTA compounds (such as #12615 and #12617), it can be used for multicolor analysis of polyhistidine-tagged proteins. Fluorescent tris-NTA compounds provide an efficient method for site-specific and stable noncovalent fluorescence labeling of polyhistidine-tagged proteins. In contrast to the transient binding of conventional mono-NTA, the multivalent interaction of tris-NTA conjugated fluorophores form a much more stable complex with polyhistidine-tagged proteins. The high selectivity of tris-NTA compounds toward cumulated histidines enables the selective labeling of proteins in cell lysates and on the surface of live cells. Fluorescent tris-NTA conjugates can be applied for the analysis of a ternary protein complex in solution and on surfaces. The transition metal ions (e.g., Ni2+)-mediated complexation of polyhistidine-labeled proteins with fluorescent tris-NTA conjugates provides a sensitive reporter for detecting and monitoring protein-protein interactions in real time.