DNA (deoxyribonucleic acid) is a nucleic acid; it contains the genetic information necessary for RNA (ribonucleic acid) and protein biosynthesis 1.
DNA is made up of two double-stranded polynucleotide chains. Each nucleotide consists of a pentose, 2-deoxy-D-ribose, to which the nitrogenous base and a phosphate group are covalently linked (N-glycosidic and phosphoester respectively). The nucleotides, in turn, are held together by "bridging" chemical bonds between the pentose molecules (phosphodiesteric chemical bond) 2-3. The two polynucleotide chains, on the other hand, are joined by hydrogen bonds (H-bonds); they are established between the complementary heterocyclic base pairs: two H-bonds between adenine (A) and thymine (T) and three H-bonds between guanine (G) and cytosine (C) 4.
To characterize the DNA (or a segment thereof) is the sequence of heterocyclic bases along the polynucleotide chain 2.
It is basically the right-handed double helix proposed in 1953 by James D. Watson and Francis H. Crick (B-form) 3.
- 1. Central Dogma of Molecular Biology. (1970) Nature. 227 (5258): 561. doi:10.1038/227561a0
- 2. Harold Hart, Christopher M. Hadad, Leslie Craine, David J. Hart. Organic Chemistry: A Short Course. (2011) ISBN: 9781111425562
- 3. J. D. WATSON, F. H. C. CRICK. Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid. (1974) Nature. 248 (5451): 765. doi:10.1038/248765a0
- 4. Harding, Stephen E., Channell, Guy, Phillips-Jones, Mary K.. The discovery of hydrogen bonds in DNA and a re-evaluation of the 1948 Creeth two-chain model for its structure. (2018) Biochemical Society Transactions. 46 (5): 1171. doi:10.1042/BST20180158