What is Tautomerization in DNA?
In DNA bases, tautomerization results in altered base pairing configurations or mispairing due to changes in hydrogen-bonding capabilities. DNA mutations are likely to be caused by such alterations. Cytosine is one of the building pyrimidine nucleobases of RNA.
What is tautomerism with example?
Tautomers are isomers of a compound which differ only in the position of the protons and electrons. Some examples of tautomerism: NOTE: The equilibrium arrows above do not intend to show the position of the equilibrium, only that an equilibrium exists between the two forms.
What is tautomerism of nitrogenous bases?
An enol structure occurs when the hydrogen atom bonds to an nearby oxygen atom that sticks out from the ring. These two types of structures are known as tautomers. Both guanine and thymine can switch easily from one tautomer to another. The change in shape affects the three-dimensional shape of the molecule.
What is the condition for tautomerism?
Answer: The condition is that it must leave at least one alpha hydrogen . Explanation: For example, acetophenone and butan-2-one show keto-enol tautomerism, but benzaldehyde and benzophenone don’t show keto-enol tautomerism, since they don’t have any alpha hydrogens.
What is the concept of tautomerism?
Tautomerism is a phenomenon where a single chemical compound tends to exist in two or more interconvertible structures that are different in terms of the relative position of one atomic nucleus which is generally the hydrogen. Tautomerism is also termed as desmotropism.
What tautomerism means?
Definition of tautomerism : isomerism in which the isomers change into one another with great ease so that they ordinarily exist together in equilibrium.
How does tautomerism cause mutations?
Mutation by tautomeric shifts in the bases of DNA. (a) In the example diagrammed, a guanine undergoes a tautomeric shift to its rare enol form (G*) at the time of replication. (b) In its enol form, it pairs with thymine.
What is tautomerism explain?
What is the condition of tautomerism?
For tautomerism, the condition is that the carbonyl group should have an alpha hydrogen which is attached to the sp3 hybridized carbon atom. Hence, four compounds as shown in above image will exhibit tautomerism.
What happens when a tautomer occurs in DNA?
The DNA bases can undergo tautomeric shifts. This can lead to mutagenesis if it occurs during DNA replication such that the new daughter strand incorporates the incorrect base pair to complement the tautomer.
Why is tautomerism important to the genetic code?
Tautomerism in DNA bases is interesting due to its possible involvement in point mutations. Watson and Crick have first suggested that the genetic code in DNA can be perturbed by the presence of a rare form of nucleobases.
Which is the leading species of tautomer in pyrimidines?
Among pyrimidine bases, cytosine has been found to show significant tautomeric activities. In fact, cytosine is the leading species (next to guanine) among nucleic acid bases in the number of tautomers.
Which is the base with the most tautomeric forms?
Among DNA bases, the purine base guanine possesses the largest number of tautomeric forms (seven of which have been detected using infrared (IR) and UV spectroscopic techniques).