What is a tautomer in DNA?
Tautomers are structural isomers that differ from one another based on the position of proton(s) and double bonds (Antonov 2014). The presence of multiple tautomers is expected to increase the structural and chemical diversity of nucleic acid bases, as shown in Figure 1.
What is the tautomer of thymine?
In the case of thymine, a number of possible tautomeric forms are possible, and an equilibrium exists between the keto (or “lactam”) form and the alternative enol (or “lactim”) form. Transformation between the two forms involves the movement of a hydrogen atom and the transfer of bonding electrons.
What are tautomeric forms?
1.8 Tautomerization. Tautomers are isomers of a molecule that exist in solution or in a cell. They are interchangeable forms because chemical bonds are rearranged many times spontaneously. This is different from chirality, where molecules are mirror images (or enantiomers) of each other (d- and l-glucose, etc.).
What is the base tautomer of adenine?
The amino groups of adenine and cytosine are hydrogen donors, and the ring nitrogen atoms (N-1 in adenine and N-3 in cytosine) are hydrogen acceptors (see below). Cytosine also has a hydrogen acceptor group at C-2. Guanine, cytosine, and thymine can form three hydrogen bonds.
Is A tautomer A mutagen?
Tautomerism as the basis of mutagenesis of natural bases has long been proposed (31–35), and substantiated in part by experimental evidence of minor tautomeric forms of both canonical bases (36–38) and certain base analogs (e.g., 5-hydroxy-2′-deoxycytidine) (39).
What is Depurination and Deamination?
Depurination; the hydrolytic removal of guanine or adenine from the #1 C (carbon) of deoxyribose in a DNA strand. Deamination: hydrolytic removal of amino (-NH2) groups from guanine (most common), cytosine or adenine. Oxidative damage of deoxyribose with any base, but most commonly purines.
Is a Tautomer a mutagen?
What is a tautomer in chemistry?
tautomerism, the existence of two or more chemical compounds that are capable of facile interconversion, in many cases merely exchanging a hydrogen atom between two other atoms, to either of which it forms a covalent bond.
What is tautomer and give example?
In tautomerism, due to the delocalization of proton, if an open structure is changed to a ring structure, then such tautomer is called as ring-chain tautomers. Glucose is an example of ring-chain tautomers.
What type of mutations are caused by intercalating agents?
Intercalating agents, such as acridine, introduce atypical spacing between base pairs, resulting in DNA polymerase introducing either a deletion or an insertion, leading to a potential frameshift mutation.
What are tautomers in nucleic acids?
Nucleic Acids: The Molecular Life Language Basics in Biology The tautomers are couples of constitutional isomers inter-convertible by a reversible chemical reaction called tautomerization. In most cases, the reaction occurs by the migration of Zinc atom of hydrogen accompanied by a change of location of a double bond.
What is the importance of tautomerism in biochemistry?
Additionally, tautomerism is important in other areas of nucleic acid biochemistry. Spontaneous formation of minor tautomeric forms of nucleic acid bases, either in the nucleotide pool or in the template strand, has been proposed to generate mutations, owing to suspected noncanonical base-pairing properties of minor tautomers.
What is tautomerism in HIV nucleoside?
Tautomerism provides a molecular explanation for the mutagenic properties of the anti-HIV nucleoside 5-aza-5,6-dihydro-2′-deoxycytidine. Proc Natl Acad Sci111: E3252–E3259. [PMC free article][PubMed] [Google Scholar] Lilley DMJ 2004. The Varkud satellite ribozyme.
What is a tautomer?
Tautomers (/ ˈ t ɔː t ə m ər /) are structural isomers (constitutional isomers) of chemical compounds that readily interconvert. This reaction commonly results in the relocation of a hydrogen atom. Tautomerism is for example relevant to the behavior of amino acids and nucleic acids, two of the fundamental building blocks of life.