Oligonucleotide synthesis

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online.Oligonucleotide synthesis is the chemical synthesis of relatively short fragments of nucleic acids with defined chemical structure (sequence). The technique is extremely useful in current laboratory practice because it provides a rapid and inexpensive access to custom-made oligonucleotides of the desired sequence. Whereas enzymes synthesize DNA and RNA in a 5' to 3' direction, chemical oligonucleotide synthesis is carried out in the opposite, 3' to 5' direction. Currently, the process is implemented as solid-phase synthesis using phosphoramidite method and A, C, G, T (2'-deoxy only), and U (ribo only) nucleoside phosphoramidites or 2'-deoxynucleoside phosphoramidites as building blocks. To obtain the desired oligonucleotide, the building blocks are sequentially coupled to the growing oligonucleotide chain in the order required by the sequence of the product (see Synthetic Cycle below). The process has been fully automated in the late 1970s.