chain terminator

Zalcitabine and didanosine are both obligate chain terminators, that have been developed for anti-HIV treatment.

These subclones were sequenced with the M13 universal primer, synthetic oligonucleotides corresponding to internal sequences and dideoxynucleotide chain terminators (15).

Furthermore nitroxides also lower oxidative damage in ischemia and related disorders6 via trapping radicals and acting as redox chain terminators.

In dye-terminator sequencing, each of the four dideoxynucleotide chain terminators is labelled with fluorescent dyes, each of which emit light at different wavelengths.

The team hoped to develop a chain terminator to halt HIV in the reverse-transcription stage of its HIV life cycle.

The latter serve as poison building blocks (chain terminators) for both viral and host DNA, causing respectively the desired antiviral effect and drug toxicity/side effects.

They inhibit the HIV reverse transcriptase enzyme competitively and act as a chain terminator of DNA synthesis.

Given a reasonable amount of DNA template, sequencing was achieved by extending oligonucleotide primers in the presence of dideoxynucleoside triphosphate chain terminators.

Chain terminators are thymidine analogues that are included in the growing DNA chain, but modified so that the chain cannot be further elongated.

Subsequently it is fully phosphorylated and the carbovir is incorporated by the RT into the DNA chain and acts as a chain terminator.

The lack of the 3'hydroxyl group which provides the attachment point for the next nucleotide in the growing DNA chain during the reverse transcription makes it an obligate chain terminator.

Like other anti-HIV nucleoside analogs, it acts as a chain terminator by incorporation and inhibits viral reverse transcriptase by competing with natural dATP.

Experiments with basic ribozymes, like Bacteriophage Qβ RNA, have shown that simple self-replicating RNA structures can withstand even strong selective pressures (e.g., opposite-chirality chain terminators).

Unfortunately, NRTIs/NtRTIs compete as substrates for not only viral but also host DNA synthesis, acting as chain terminators for both.

These treatments rely on the kinase activation of the analogs, which then are incorporated into the DNA of the tumor cell or virus to act as DNA chain terminators.

NRTIs are chain terminators such that once incorporated, work by preventing other nucleosides from also being incorporated into the DNA chain because of the absence of a 3' OH group.

In chain terminator sequencing (Sanger sequencing), extension is initiated at a specific site on the template DNA by using a short oligonucleotide 'primer' complementary to the template at that region.

Sofosbuvir, on the other hand, is metabolized to the active uridine analog triphosphate, which acts as a RNA chain terminator when incorporated into the RNA via the NS5B polymerase.

Once they are phosphorylated, they work as antimetabolites by being similar enough to nucleotides to be incorporated into growing DNA strands; but they act as chain terminators and stop viral DNA Polymerase.

Inhibition is of two kinds DNA chain terminators which stop viral DNA synthesis non-nucleoside reverse transcriptase inhibitors which bind to reserve transcriptase (the enzyme responsible for reverse transcription), preventing its action.

For example, E. coli DnaG will use 2',3'-dideoxynucleoside 5'-triphosphates (ddNTPs) as substrates, which act as chain terminators due to the lack of a 3' hydroxyl to form a phosphodiester bond with the next nucleotide.

Herpes simplex virus thymidine kinase (HSV-tk) has been used extensively as a so-called suicide gene, since administration of ganciclovir will be followed by its phosphorylation by HSV-tk to yield a chain terminator for DNA synthesis.

At the time the patent application was filed, Glaxo Wellcome knew that AZT was suitable for prolonged treatment of humans, that compounds of its class could act as chain terminators, and that in vitro efficacy had been shown in human cells.

Its limitations include dye effects due to differences in the incorporation of the dye-labelled chain terminators into the DNA fragment, resulting in unequal peak heights and shapes in the electronic DNA sequence trace chromatogram after capillary electrophoresis (see figure to the left).

Once incorporated into the DNA chain, the absence of a 3'-hydroxyl group, which normally forms the 5'- to 3'- phosphoester bond with the next nucleic acid, blocks further extension of the DNA by RT, and they act as chain terminators.