DNA is composed of two strands, the wind approximately each other. Each strand has actually repeating systems of a nitrogenous base, deoxyribose sugar, and also a phosphate group. Over there are several interactions present within a strand and also between two strands the stabilize the DNA.

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Covalent bonds (intrastrand bonds)

Each strand is composed of the following:

Base (Adenine, Thymine, Guanine, Cytosine)Deoxyribose sugarPhosphate group

There are 4 bases: Adenine and also Guanine (purines); Cytosine and Thymine (Pyrimidines). Purines have two carbon-nitrogen ring while pyrimidines have actually a single carbon-nitrogen ring. Thus, there are four different nucleotides that have the right to be integrated into DNA.

Based ~ above which basic is attached, the nucleotides are referred to as 2’-deoxyadenosine triphosphate, 2’-deoxycytidine triphosphate, 2’-deoxyguanosine triphosphate, or 2’-deoxythymidine triphosphate. Every of this bases is associated to 1’-carbon of the deoxyribose sugar.

In one unattached and complimentary nucleotide, over there is a triphosphate team on the 5’-carbon of the deoxyribose sugar. However, as soon as a nucleotide is incorporated into a DNA strand, that loses 2 of the phosphate groups and only one phosphate team is included to the DNA strand.

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This enhancement involves formation of a covalent bond called the phosphodiester bond. This is formed between the 5’-phosphate group of one nucleotide and also the 3’-OH group of an additional nucleotide creating a sugar-phosphate backbone the DNA.

Hydrogen bonds

The hydrogen bonds between the basic pairs type the double helical framework of DNA. Over there is no exchange or sharing of electron in hydrogen bonds as viewed in covalent or ionic bonds. Hydrogen bonds take place over quick distances and also can be easily formed and also broken. Although individually each hydrogen link is lot weaker than the covalent bond, they can stabilize the twin helix since of their large numbers.

This pairing is really specific: adenine pairs v thymine and also cytosine pairs with guanine. This selective pairing is dubbed ‘complementary basic pairing’. A-T pair forms two hydrogen bonds, when C-G pair forms three. The sugar-phosphate chains type the backbone that the ladder-like DNA structure and also these base pairs type the rungs. The broad of each of these ‘rungs’ room the exact same as it involves one purine (A or G) and also one pyrimidine (C or T) base.

Stacking interactions

a) Hydrophobic effects

DNA has an interesting arrangement wherein the non-polar, uncharged bases are present in the internal of the structure, when the negatively charged phosphates are present on the outside. Together the cellular environment is aqueous and polar, the hydrophobic bases in the interior of the helix are maintained away indigenous the neighboring water and also the hydrophilic heads room exposed and interact through the exterior water. This property increases the solubility that DNA in water.

b) valve der Waals forces

The nitrogenous bases stack upon one another are spaced based upon their valve der Waals distance. Van der Waals distance is the distance at which 2 molecules are attracted to every other. If this distance reduces, the electron of the two molecules may overlap resulting in repulsion. These forces are very distance dependent and are inversely proportional to the sixth power of street (r6 ). Although a solitary van der Waals interaction has actually a very tiny effect on the as whole structure of DNA, the net impact of number of interactions lead to comprehensive stability.

c) Ionic interactions

The electrostatic (ion-ion) repulsion the the negatively charged phosphates on the external can do DNA potentially very unstable. However, magnesium ion (Mg2+) and cationic proteins in addition to arginine and also lysine residues interact with the negative charged groups in the DNA and also stabilize it.

The strength and stability that DNA stacking interactions has been scientifically proved by demonstrating that the use of compound (urea, formamide) the interfere v hydrogen bonds perform not different the strands completely, saying the existence of added forces at work.


Written by

Dr. Surat P

Dr. Surat graduated with a Ph.D. In cell Biology and also Mechanobiology native the Tata academy of basic Research (Mumbai, India) in 2016. Prior to her Ph.D., Surat studied for a Bachelor of scientific research (B.Sc.) level in Zoology, throughout which she to be the recipient of an Indian Academy of scientific researches Summer Fellowship to research the proteins associated in AIDs. She produces feature posts on a wide variety of topics, such as medical ethics, data manipulation, pseudoscience and also superstition, education, and also human evolution. She is passionate about science communication and also writes write-ups covering all areas of the life sciences.

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P, Surat. (2019, February 26). Interactions That organize DNA Together. Gimpppa.org. Re-cover on September 21, 2021 indigenous https://www.gimpppa.org/life-sciences/Interactions-That-Hold-DNA-Together.aspx.


P, Surat. "Interactions That hold DNA Together". gimpppa.org. 21 September 2021. .


P, Surat. "Interactions That host DNA Together". Gimpppa.org. Https://www.gimpppa.org/life-sciences/Interactions-That-Hold-DNA-Together.aspx. (accessed September 21, 2021).

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P, Surat. 2019. Interactions That hold DNA Together. Gimpppa.org, perceived 21 September 2021, https://www.gimpppa.org/life-sciences/Interactions-That-Hold-DNA-Together.aspx.