Oligonucleotides, formation

The terminal phase, which shows an increasingly slower, further increase in the hyperchromic shift and acid-soluble oligonucleotide formation. Both phenomena, however, are no more linear with number of... 

Simultaneous peptide and oligonucleotide formation has been examined on a mixture of amino acid, nucleoside triphosphate, imidazole, and MgCl2 as reviewed in the previous section. In this reaction the oligonucleotide probably forms via nucleoside 5 -phosphorimidazolide 36). The yield of dinucleotide from ATP is up to 0.12%, the... 

Solutions of that type are improbable. In exchange for a simplification mixture of the formose reaction, we must specify the presence of glycolaldehyde, glyceraldehyde, and borate minerals (and the absence of many potentially interfering substances, such as cyanide) and a route by which the protective borate will be removed so that the route to oligonucleotide formation remains open. Ribose is only one of the six components present in RNA. An extended number of steps involving the synthesis, purification, transportation, and highly specific... 

During studies on oligonucleotide formation with excess l-(mesitylene-2-sulfonyl)-l, 2,4-triazole (MSNT) or tetrazole, Reese discovered that protected uridines are converted at room temperature into the chemically stable 1,2,4-triazole derivatives in high yields (80MII). Reese... 

With modified oligonucleotides formation of secondary structures by base pairing may result in separate signals for one compound. This effect appears most frequently with G-rich sequences. To avoid this effect, gels and buffers in ODN-CE are generally prepared in the presence of 7 M urea or formamide. Other options for analysis of dG-rich ODNs include a... 

The urea-ammonium chloride-phosphate system offers a method for the formation of short-chain oligoribonucleotides on the primitive earth. It does not appear to be applicable to the formation of oligodeoxyribonucleic acids since no oligonucleotide formation was evident after 44 days of heating at 65°C of a mixture of thymidine, urea, ammonium chloride and phosphate. (See also references 29, 30 and 31.)... 

Sawai, H. (1988) Oligonucleotide formation catalyzed by divalent metal ions. The uniqueness of the nbosyl system. J. Mol. Evol. 27, 181-186. 

Bu4N F , THF, Pyr, H2O, rt, 30 min. These conditions result in the formation of a mixture of fluorophosphate and phosphate. In the case of oligonucleotides, some intemucleotide bond cleavage is observed with this reagent. 

The rate of oligonucleotide synthesis by the triester method using mesitylenesul-fonyl chloride was increased five- to tenfold when this group was used as a protective group during intemucleotide bond formation. It was removed with coned. NH4OH at 60° for 12 h or by the oximate method. ... 

Antisense therapy means the selective, sequence-specific inhibition of gene expression by single-stranded DNA oligonucleotides. By hybridizing to the target mRNA, which results in a subsequent double-helix formation, gene expression is blocked. This process can occur at any point between the conclusion of transcription and initiation of translation or even possibly during translation. 

Carbodi-imides are used to mediate the formation of amide linkage betwen a carboxylate and an amine or phosphoramidate linkages between a phosphate and an amine [12]. The following is essentially the method of Rockwood [13] and is modified to give a phospho-diester link between the terminal monophosphate of the oligonucleotide and the hydroxyl group of 2-hydroxyethyl disulfide (HEDS) [14]. 

In the early solution phase syntheses of oligonucleotides, coupling of phosphate diesters was used. A mixed 3 -ester with one aryl substituent, usually o-chlorophenyl, was coupled with a deprotected 5 -OH nucleotide. The coupling reagents were sulfonyl halides, particularly 2,4,6-tri-i-propylbenzenesulfonyl chloride,53 and the reactions proceeded by formation of reactive sulfonate esters. Coupling conditions... 

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