Ase pairs with either C or T.7 This is made possible

Ase pairs with either C or T.7 This is made possible by the ability of P and K to form both amino and imino tautomers, as shown in Figure 3. Oligonucleotides containing one or more P substitutions were found5 to form duplexes of stability equivalent to the parent sequence and exhibited sharp transitions on melting. Substitution with one or more K residues led to duplexes of reduced but still effective stability. Glen Research is now offering the CE phosphoramidite of P which is equivalent to a C/T mix and of K which is equivalent to an A/G mix. The structures of the CE phosphoramidites are shown in Figure 2. A P/K mix to be equivalent to an N (A/C/G/T mix) is also offered, as are the corresponding supports. 5-METHYL-ISOCYTIDINE / ISOGUANOSINE BASE PAIR
hile attempts are being made to simplify the genetic code by the use of universal and degenerate bases, it remains a topic of more than academic interest to extend the genetic code by the addition of new base pairs. A non-standard base pair which has received considerable attention is that formed between isocytosine (isoC) and isoguanine (iso-G). Indeed, isoguanosine is a naturally occurring ribonucleoside known as crotonoside. A standard Watson and Crick base pair is formed between iso-C and iso-G, but the hydrogen bonding pattern, shown in Figure 1, is quite different from the natural base pairs A-T and C-G.1 (The 5-methyl analogue, as shown in Figure 1, was chosen as the synthetic target due to the reported2 instability of 2’deoxyisocytidine caused by deamination during oligonucleotide synthesis or deprotection.) Since 5-methyl-2′-deoxyisocytidine (5-Me-isodC) and 2′-deoxyisoguanosine (isodG) are both very susceptible to cleavage of the glycosidic bond under acidic conditions, we chose formamidine protecting groups for both. Therefore, 5Me-isodC was protected at the N2 position and isodG at the N6 position with diisobutyl formamidine. The O2 position of isodG was protected with diphenylcarbamoyl (DPC) which is labile under standard ammonium hydroxide deprotection conditions. [A recent publication2 describes the use of a 4nitrophenyl protecting group for the O2 position but this requires an additional deprotection step (20% DBU/ acetonitrile) prior to the ammonium hydroxide deprotection.26305-03-3 SMILES ] The structures of the two CE phosphoramidite monomers are shown in Figure 1.112809-51-5 Description Even with the use of formamidine protecting groups designed to stabilize the glycosidic linkages, oligonucleotides containing these modified bases should be prepared using dichloroacetic acid (DCA) rather than trichloroacetic acid (TCA) in the deblocking mix.PMID:30252275 Most synthesizers already use DCA in the deblocking mix. The exception is Applied Biosystems synthesizers and an alternative deblocking mix containing DCA is available from Glen Research. Base composition analyses was carriedisodG 5-Me-isodC CE Phosphoramidites out on two 17mers containing three 5Me-isodC and three isodG residues, respectively. The results, shown in Figure 2, confirm that these labile deoxynucleosides are still capable of producing accurate oligonucleotides with minimal degradation. Digestion and HPLC conditions are available on request. NEW PROTECTING GROUPS FOR DNA, RNA AND 2′-OMe-RNA MONOMERS
2′-OMe-Ac-C, 2′-OMe-5-Me-C and 2′-OMe-I ltraFAST DNA deprotection1 has revolutionized the downstream processing of oligodeoxynucleotides by cutting the cleavage and deprotection steps to less than 15 minutes. Glen Research has extended this utility to 2′-OMe-RNA wit.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