S of TO are additive, with the most stable triplex at neutral pH evidenced by a Tm = +45 (compared to that of the unmodified TFO). This stability is accompanied by large enhancements in fluorescence (26-fold increase at pH 7) and quantum yields (up to 40-fold).20 The simplest way to incorporate TO into an oligonucleotide is to employ its NHS ester in post synthetic labelling of the corresponding amino-modified oligonucleotide. Various amino-modifiers are commercially available for incorporation into oligonucleotides at the termini or internally, and the labelling method is straightforward and generally high yielding. One example is the use of an internal aminomodifier C6 dT nucleobase (Figure 2A), which places the fluorescent label in the major groove upon duplex formation. Once the oligonucleotides are labelled, purification is carried out via HPLC (Figure 2B). exonuclease activity of Thermus aquaticus DNA polymerase.
New Product — Thiazole Orange NHS Ester
The Brown Group recently investigated the design of thiazole orange (TO) oligonucleotide probes for DNA and RNA.1 The researchers evaluated a series of different sequences, TO conjugation locations, and TOs in the context of duplex stability, fluorescence, and CD. The data presented provide a wealth of information on TO probe design. Among the different TOs that were studied in this publication, a TO ligand that contained a hexanoic acid linker attached to the benzothiazole (Figure 1) was particularly interesting. This ligand was conjugated to short oligonucleotides containing a single internal amino-modifier. There were twelve DNA oligonucleotides in total, 4 different sequences multiplied by 3 different locations (2′ position of ribose and 2 versions of 5-aminomodified-dU). Each one was hybridized to its complementary sequence for duplex stability and fluorescence analysis. For these oligonucleotides, the results were significant and found to be dependent on the sequence, as well as where the TO was attached on the oligonucleotide. Melting temperatures were elevated by up to 14.6 , with an average of 10.1 relative to unmodified controls. This stabilization was relatively consistent regardless of whether the TO was on the nucleobase or the sugar. In addition, the hybridization was accompanied by a fluorescent enhancement of up to 8.6fold, with an average of 3.9-fold. This “lighting up” effect on hybridization was even more significant when the probe was synthesized with a 2′-OMe backbone, mainly due to the fact that the 2′-OMe had much less singlestranded fluorescence.1422365-94-3 Description Unlike the melting temperature data, this enhancement notably increased when the TO was attached to the nucleobase.3133-16-2 Molecular Weight In order for researchers to better explore the use of TO in the fluorescence imaging of DNA and RNA, we are adding this particular TO NHS ester to our offerings.PMID:30020680 In our hands, the TO NHS ester couples very well. In one test, TO was coupled to

amino-modifier C6-T11. The oligonucleotide (previously desalted with a Glen Gel-Pak) was dissolved in aqueous sodium bicarbonate and mixed with a solution of TO NHS ester in DMSO (~5.5 eq). After incubation at room temperature for fifteen minutes, the reaction was desalted using another Glen Gel-Pak cartridge and analyzed by RP-HPLC (Figure 2). The amino-labeled oligonucleotide was completely consumed, giving a later eluting peak that contained TO. We also observed a second, much smaller (~4 %) TO-labeled oligonucleotide peak. ESI-MS analysis gave the desired TO-.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com