Some RNAs Function Like Enzymes

Editing of the cytochrome b message in the flagellated protozoan Leishmania tarentolae. Editing, which involves the insertion of 11 U residues, creates a translatable RNA where no translation was possible before. Structure shown for mRNA is after editing. 

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Some RNAs Function Like Enzymes Some RNAs Are Self-Splicing Some Ribonucleases Are RNAs Ribosomal RNA Catalyzes Peptide Bond Formation Catalytic RNA May Have Evolutionary Significance Inhibitors of RNA Metabolism... 

Like bacteria, eukaryotes have several types of DNA polymerases. Some have been linked to particular functions, such as the replication of mitochondrial DNA. The replication of nuclear chromosomes involves DNA polymerase a, in association with DNA polymerase S. DNA polymerase a is typically a multisubunit enzyme with similar structure and properties in all eukaryotic cells. One subunit has a primase activity, and the largest subunit (Afr -180,000) contains the polymerization activity. However, this polymerase has no proofreading 3 —>5 exonuclease activity, making it unsuitable for high-fidelity DNA replication. DNA polymerase a is believed to function only in the synthesis of short primers (containing either RNA or DNA) for Okazaki fragments on the lagging strand. These primers... 

All drug action is likely, at some stage, to involve interaction with the many phosphorus compounds already present in the body. In many cases, this is known to be cellular DNA. Drug action can involve interference with DNA replication, the synthesis of cell walls, proteins or essential enzymes, or the function of ion channels and receptors [7,8]. Synthetic oligonucleotides and oligopeptides show much promise as drugs capable of interacting with body DNA (or RNA). 

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