Many studies have demonstrated PNA’s suitability for modifying gene expression, mostly in molecular test-tube experiments and in cell cultures. PNA’s unique properties potentially give it several advantages over antisense DNAs and RNAs, including more versatility in binding to DNA as well as RNA, stronger binding to its target and greater chemical stability in the enzyme-laden cellular environment. Such drugs would be conceptually similar to “antisense” compounds, such as short DNA or RNA strands that bind to a specific RNA sequence to interfere with the production of disease-related proteins. We sought to design drugs that would work by acting on the DNA composing specific genes, to either block or enhance the gene’s expression (the production of the protein it encodes). My group developed PNA more than 15 years ago in the course of a project with a rather more immediately useful goal than the creation of unprecedented life-forms. That is, they hope to put together a novel combination of molecules that can self-organize, metabolize (make use of an energy source), grow, reproduce and evolve.Ī molecule that some researchers study in pursuit of this vision is peptide nucleic acid (PNA), which mimics the information-storing features of DNA and RNA but is built on a proteinlike backbone that is simpler and sturdier than their sugar-phosphate backbones. Yet scientists dream of synthesizing life that is utterly alien to this world-both to better understand the minimum components required for life (as part of the quest to uncover the essence of life and how life originated on earth) and, frankly, to see if they can do it. The proteins, in turn, serve as important structural elements in tissues and, as enzymes, are the cell’s workhorses. All these organisms are based on nucleic acids-DNA and RNA-and proteins, working together more or less as described by the so-called central dogma of molecular biology: DNA stores information that is transcribed into RNA, which then serves as a template for producing a protein. The genotype is determined by the sequence of bases.For all the magnificent diversity of life on this planet, ranging from tiny bacteria to majestic blue whales, from sunshine-harvesting plants to mineral-digesting endoliths miles underground, only one kind of “life as we know it” exists. It is this base sequence which forms the genetic code. This creates the twisting double helix structure of DNA.Īll cells store their genetic information in the base sequence of DNA. The two strands of DNA are antiparallel which means that one strand runs in a 5’ to 3’ direction and the other runs in a 3’ to 5’ direction. the 3' end (said as "3 prime end") at the deoxyribose end.the 5' end (said as "5 prime end") at the phosphate end.These strong bonds form a sugar-phosphate backbone. These basic units are linked together to form strands by strong bonds between the deoxyribose sugar of one nucleotide and the phosphate of the next nucleotide. They always pair up in a particular way, called complementary base pairing: There are chemical cross-links between the two strands in DNA, formed by pairs of bases held together by hydrogen bonds. The nucleotides are identical except for the base, which can be one of four bases:
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