Peptide nucleic acid, abbreviated as PNA, is an artificial polymer that bears many similarities to deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). It is used by scientists and physicians in medical treatments and biological research. Peptide nucleic acid combines two advantages that make it useful for these applications. First, it has the ability to store information, just like DNA, but has an even more robust backbone than DNA does. This second property gives it a great deal of chemical stability. Peptide nucleic acid has never been known to occur naturally, but some speculate that it may have been present during the earlier history of Earth.
The research that has been done involving peptide nucleic acid has led to some hypotheses that these molecules may have been part of the earliest forms of life on Earth. PNA might have been used as their version of DNA because of its chemical strength and its simpler structure. Intriguingly, it is also possible for PNA to form and polymerize in water under certain conditions. These conditions include a temperature of at least 210 degrees Fahrenheit (100 degrees C).
Water typically boils at this temperature at sea level, but such may not have been the case long ago. Many scientists theorize that the Earth's atmosphere was much more dense at certain times during its development, and this would effectively raise the boiling point of water. Also, water in deep oceans, possibly heated by volcanic activity, would be under greater pressure and thus have a higher boiling point.
Because of the relationship that PNA has to DNA, some scientists have proposed yet another interesting application for it. Those who work to construct artificial life forms have looked to peptide nucleic acid as a possible ingredient in their research and designs. The dream that some scientists have of synthesizing life could be greatly helped by the versatility of PNA, and the way it mimics the information storage ability of DNA.
At the present time, peptide nucleic acid has found use as a tool in medical research. PNA can interact with DNA on the molecular level in such a away as to be able to suppress or promote a certain genetic trait, if it is properly engineered. Drugs based on this principle could be useful, for example, in suppressing a gene that leads to susceptibility to a certain disease. Alternately, they could enhance the expression of a gene that lends immunity to a certain disease. Such drugs, if developed, would require a great deal of testing before they were implemented, but could hold promising implications for the future of medicine.