resonance energy transfer

EDANS (EDANS acid [5-((2-Aminoethyl)amino)naphthalene-1-sulfonic acid]) is a novel and quenched fluorogenic substrate for assaying retroviral protease by resonance energy transfer (RET).

NBD-PE is a lipid dye used primarily as a probe to study lipid organisation and dynamics within cell membranes and also to study membrane fusion by fluorescence resonance energy transfer (FRET), Ex=463 nm, Em=536 nm.

UBQ-3 NHS ester is a fluorescent agent featuring a terminal NHS ester group. It has a broad quenching range of 620–730 nm, enabling it to be used as an acceptor for fluorescence resonance energy transfer (FRET) applications with far-red to near-infrared dyes, such as Cy5, Cy5.5, Alexa Fluor 633, 647, 700. The NHS ester can label proteins, amine-modified oligonucleotides, and other amine-containing primary amines (-NH2).

QSY-9-succinimidyl ester is a non-fluorescent acceptor molecule featuring a terminal NHS ester group. Its quenching range is broad and intense, spanning 500-600 nm, which makes it suitable as an acceptor for fluorescence resonance energy transfer (FRET) applications with fluorescent dyes in the same wavelength range. The NHS ester can label primary amines (-NH2) on proteins, amine-modified oligonucleotides, and other amine-containing molecules.

QSY-21 is a fluorescence quencher with broad absorption in the far-red and near-infrared regions, effectively quenching the fluorescence of dyes that emit in these areas. It is a carboxylic acid derivative with a strong maximum absorption at 661 nm, making it a suitable acceptor for fluorescence resonance energy transfer (FRET) applications. QSY-21 is commonly used as a quencher for Cyanine5, Cyanine5.5, AF 647, or other spectrally similar fluorescent dyes.

BHQ-2 NHS is a non-fluorescent dark quencher featuring a polyaromatic azo framework and a terminal NHS ester. It exhibits a broad and intense quenching range between 560-670 nm, making it suitable for use as an acceptor in fluorescence resonance energy transfer (FRET) applications with orange to far-red emitting dyes. The NHS ester allows labeling of proteins, amine-modified oligonucleotides, and other primary amine (-NH2) containing molecules.

BI 2852 FL is a cell-permeable bioluminescence resonance energy transfer (BRET) fluorescent probe targeting the pan-RAS type. It is synthesized by conjugating a fluorophore with a derivative of the reversible SI/II-P KRAS inhibitor, BI 2852. BI 2852 FL is employed in a competitive BRET format to quantify the binding of SII-P to multimeric RAS complexes within living cells.

BODIPY FL VH032 is a high-affinity VHL fluorescent probe (Kd= 3.01 nM) with application in time-resolved fluorescence resonance energy-transfer (TR-FRET) assays for high-throughput identification and characterization of VHL ligands. BODIPY FL VH032 consists of a derivative of von Hippel-Lindau (VHL) ligand VH 032 and a fluorophore BODIPY FL(with excitation peak at 504 nm and emission peak at 520 nm), joined by a polyethylene glycol (PEG) 4 linker. The BODIPY FL VH032 VHL TR-FRET signal is stable through the 90 - 300 min incubation time, and theTR-FRET binding assay is sensitive, selective and resistant to assay interference. BODIPY FL VH032 also exhibits high VHL affinity in a fluorescence polarization (FP) assay. Excitation maximum ~ 504 nm; emission maximum ~ 520 nm.

Coelenteramine 400a (Coelenterazine 400a), a Coelenterazine derivative, serves as a substrate for Renilla luciferase (RLuc), facilitating the emission of blue light at 395 nm [1] [2]. This compound alters the bioluminescence color of RLuc by substituting the sulfur and oxygen heteroatoms in the methylene bridge. Coelenteramine 400a enhances signal resolution, proving useful in bioluminescence resonance energy transfer (BRET) research [3].

Mca-(endo-1α-Dap(Dnp))-TNF-α(-5 to +6) amide (human) TFA is a peptide that functions as a fluorescence resonance energy transfer (FRET)-based substrate, with its activity determined by the change in fluorescence intensity following cleavage [1].

Mca-SEVNLDAEFK(Dnp)-NH2 is a fluorogenic substrate featuring a 7-methoxycoumarin moiety whose fluorescence is quenched by the adjacent 2,4-dinitrophenyl group through resonance energy transfer. This compound serves as a probe for assessing peptidase activity; enzymatic cleavage of the amide bond separating the fluorophore and quencher results in increased fluorescence. It is particularly useful for quantifying the activity of BACE-1 [1].

MCA succinimidyl ester, a derivative of MCA, selectively reacts with amines and serves as a peptide substrate for fluorescence resonance energy transfer (FRET) [1].

Europium W1024 isothiocyanate (ITC) is a lanthanide-based fluorophore characterized by its long emission lifetime and significant Stokes shift, featuring excitation and emission maxima at 340 and 613 nm, respectively. This compound includes a reactive isothiocyanate handle that engages with primary amino groups in alkaline conditions. It maintains stability under high temperatures, in the face of elevated EDTA concentrations, or at low pH levels, though it falters when exposed to manganese. Commonly, Europium W1024 ITC serves as a donor fluorophore in time-resolved fluorescence resonance energy transfer (TR-FRET) applications, offering the advantage of a prolonged measurement window for observing acceptor fluorescence and minimizing autofluorescence interference through its extended emission lifetime.

CoraFluor 1, an amine-reactive terbium-based compound, serves as a potent donor in time-resolved Förster resonance energy transfer (TR-FRET) assays, including applications in target engagement and ternary complex assessments. Its formulation, featuring a PFP ester, allows efficient bonding with primary amines, thus facilitating the labeling of various biomolecules like antibodies, nanobodies, proteins, and peptides. Notably, CoraFluor 1 surpasses other TR-FRET donors in brightness, assay sensitivity, and stability within biological environments. Additionally, it is fully compatible with prevalent acceptor dyes, including FAM, TMR, and Cyanine 5, SE, making it an ideal choice for high-throughput screening endeavors.

CELT-211 is a potent, selective fluorescent ligand for the h5HT2B serotonin receptor, demonstrating full selectivity over h5HT2A and h5HT2C receptors with a Ki value of 56.3 nM in radioligand binding assays for h5HT2B receptors. Its excitation and emission maxima are 589 nm and 616 nm, respectively, making its wavelengths compatible with its application as an acceptor dye in Time-Resolved Fluorescence Resonance Energy Transfer (TR-FRET) assays when paired with the CoraFluor 1 TR-FRET donor.

NFQ1, a non-fluorescent quencher (absorption wavelength: 474 nm), is used for a new type of One Sample Fluorescence Resonance Energy Transfer (OS-FRET) method, enabling measurement of unquenched donor emission in the same sample. NFQ1 shows a broad absorption spectrum, ensuring its utility as a dark acceptor for many donors [1].