A French team at the Max Mousseron Institute for Biomolecules (Montpellier) developed the use of a bromohexyl phosphoramidite and different solid supports to allow conjugation and modifications.11 Our first proposal is to carry out the conjugation post-synthesis of an amino-modified oligonucleotide with an 8
Figure 1: clicK chemistry structures
R
azide N-hydroxysuccinimide (NHS) ester, Azidobutyrate NHS Ester (2). This method is efficient for azido-modification of amines at either the 3′-end or the 5′-end of an oligo and it can even be used for internal modification on an Amino-Modifier-C6 dX residue within the sequence. The second approach, specific to the 5′-terminus, consists of adding 5′-Bromohexyl Phosphoramidite (3) in the last cycle. This modifier can then be easily transformed into a 5′-azido group by displacement of bromide using sodium azide. The first method can be performed in solution while the other allows the azide addition to be performed in solid phase on the synthesis column prior to cleavage and deprotection of the oligonucleotide. These products are easy to use and should prove valuable additions to our catalog. aziDoButyrate use In this case, oligonucleotides are synthesized as usual on any synthesizer. Amino groups have to be introduced either at the 3′ or at the 5′ end of the oligonucleotide. After cleavage and deprotection, the azido group can be introduced as a modification of the amine. For example, the oligonucleotide in sodium carbonate/sodium bicarbonate buffer (pH 8.75) was incubated at room temperature with succinimidyl-4-azidobutyrate in DMSO. The final oligo is then purified using HPLC or precipitated with ethanol or butanol.
BroMohexyl use The 5′-Bromohexyl Phosphoramidite is used to make 5′-bromohexyl oligonucleotides with the same phosphoramidite elongation cycle used for the coupling as the regular 2′-deoxynucleoside phosphoramidites. Bromohexyl ODNs were then converted into azidohexyl ODNs on the column by treatment of the CPG with a solution of sodium azide and sodium iodide in dry DMF at 65 . Finally, the CPG with the 5′-azido oligo is treated with ammonia affording 5′-azidohexyl-ODNs in solution.11 cyclization anD ligation oF oligos using click cheMistry. To exemplify the use and possibilities of this chemistry, we reference some work carried out in Professor Tom Brown’s laboratory at the University of Southampton (UK).10 This paper describes a templatedirected oligonucleotide strand ligation, a covalent intramolecular DNA circularization and a catenation experiment using Click Chemistry.186692-46-6 Synonym Tom Brown’s group also described the formation of a very stable cyclic DNA mini-duplex with just two base pairs, as an extension of this work.1397-89-3 manufacturer 12 These experiments rely on an efficient and simple method of oligonucleotide click ligation that produces an unnatural extended DNA backbone linkage.PMID:30725695 One of the reacting ODNs contains a 3′-azide and the other a 5′-alkyne. The 5′-alkyne
can be introduced using our 5′-Hexynyl Phosphoramidite (1). For the oligonucleotide ligation reactions, the authors10 decided to use a strategy where a Cu[I] click catalyst was prepared in situ from Cu[II] sulfate and sodium ascorbate. All ligation reactions were carried out in 0.2 M aqueous sodium chloride to ensure complete formation of a duplex with the template. Unfortunately, under these conditions extensive degradation of all ODNs occurred, even with degassed buffers. However, the water-soluble tristriazolylamine Cu[I]-binding ligand13 g.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