Reverse transcriptase-polymer chain

Figure 6. Amplification of RNA molecules by assays that are sequence- insensitive. The first assay (upper part) combines the polymerase chain reaction (PCR) of DNA templates with reverse transcription and transcription. Commonly used enzymes are TAQ-polym-erase, HIV reverse transcriptase and bacteriophage T7 RNA polymerase. The assay requires a temperature program applying higher temperatures for double strand dissociation. The second assay (lower part) shows the self-sustained sequence replication reaction (3SR) which can be carried out isothermally because double strand dissociation is replaced by enzymatic digestion of the RNA strand in the RNA-DNA duplex. The enzymes used are HIV reverse transcriptase, RNase H and T7 RNA polymerase.

An ansamycin antibiotic produced by Streptomyces spectabilis with antibacterial (against tuberculosis pathogens), antiviral, and antitumor activities. S. occurs as a multi-component mixture of up to ten individual compounds (S. A to G, J, K, and U) with S. C (methyl streptovaricate, C4oH5,NO,4, Mr 769.84, amorphous, mp. 189-191 °C, [a][) 4-602°) as the main component. The S. are inhibitors of bacterial RNA-polyme-rase as well as the reverse transcriptase of oncogenic viruses. The biosynthesis of the aromatic core branches off from the shikimic acid pathway while the alkyl chain is formed on the polyketide pathway. 

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