On the oligonucleotide during cleavage and deprotection steps. It should be removed in aqueous acid after removal of the ammonia. The MMT group can, of course, also be used in reverse phase purification techniques. Alternatively, the MMT group can be removed on the synthesizer to allow amine-specific reactions to be carried out in the synthesis column. 2′-F-Pyrimidines 2′-Deoxy-2′-fluoro-nucleosides adopt an RNA-type sugar conformation, presumably due to the high electronegativity of fluorine. Because of this sugar conformation, RNA duplexes (A-form) are generally more thermodynamically stable than DNA duplexes (B-form). As expected, the addition of 2′-F-RNA residues to oligodeoxynucleotides progressively increases the thermal stability of their duplexes with RNA. The stabilization is additive at approximately 2per residue. This compares favorably with 2′-OMeRNA at around 1.5and RNA at 1.1per residue. In the meantime, base pair specificity remains intact.4 2′-F-RNA phosphodiester linkages are not nuclease resistant, although the corresponding phosphorothioate linkages are highly resistant. Researchers usually design antisense oligonucleotides to form duplexes with RNA which are substrates for RNase H. Uniformly modified 2′-FRNA/RNA duplexes are not substrates for RNase H. However, it is straightforward to prepare chimeric 2′-FRNA/DNA phosphorothioate oligonucleotides which exhibit enhanced binding to the RNA target, are substrates for RNase H, and are highly nuclease resistant. Following many requests from our customers, we are now introducing 2′-FC (3) and 2′-F-U (4) phosphoramidite monomers. If we are able to supply the corresponding A and G monomers at a reasonable price, we will introduce them later. 5,6-Dihydro-dU and dT Cellular DNA is constantly being damaged by oxidation and alkylation, by free radicals, and by ultraviolet and ionizing radiation. The body has
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therefore evolved a number of repair enzyme systems to excise and repair these lesions.76343-93-6 manufacturer The study of the resulting lesions and the enzymes responsible for their repair is currently a major area of scientific research.5 One group of compounds of particular interest are the 5,6-dihydro pyrimidines. They are a naturally occurring class of compounds that are structural components of alanine transfer RNA. Dihydrouracil is also a major base damage product formed by exposure of cytosine in DNA to ionizing radiation under anoxic conditions.99-66-1 References A major difficulty in the study of damaged nucleobases is their inherent instability.PMID:29083824 This has made it difficult to incorporate them into synthetic oligonucleotides for model studies since they must be stable to the conditions used for oligonucleotide synthesis, cleavage and deprotection. This makes it necessary to do most experiments using preparations of DNA which are then exposed to various agents followed by isolation and characterization of the damaged products. However, the use of our UltraMILD monomers allows strongly basic hydrolytic conditions to be avoided during cleavage and deprotection, opening the possibility that oligos incorporating some damaged bases might be synthesized. Oligonucleotides synthesized using 5,6-dihydro-dU (5) or 5,6-dihydro-dT (6) and UltraMILD monomers can be cleaved using either concentrated ammonium hydroxide or 50 mM potassium carbonate in anhydrous methanol. Complete cleavage and deprotection can be accomplished at room temperature in 2-4 hours without damaging either the dihydro-dU or dihydro-dT.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