What type of mutation can arise due to Keto-enol tautomerism?

What type of mutation can arise due to Keto-enol tautomerism?

Hydrogen transfer in DNA bases leads to the creation of short-lived biologically relevant mutagens; referred to as tautomers. Keto–enol and amino–imino tautomerism are thought to be candidates for spontaneous mutation of DNA during replication and repair.

What is Keto-enol tautomerism in DNA?

In organic chemistry, keto-enol tautomerism refers to a chemical equilibrium between a keto form (a ketone or an aldehyde) and an enol. The enol and keto forms are said to be tautomers of each other.

What happens in Keto-enol tautomerism?

Keto implies that the tautomer contains a carbonyl bond while enol implies the presence of a double bond and a hydroxyl group. The keto-enol tautomerization equilibrium is dependent on stabilization factors of both the keto tautomer and the enol tautomer.

What is Tautomerization mutation?

A tautomeric shift in one strand has produced a transition mutation in the complementary strand. If the mutation occurs in the germline, it will be transmitted to future generations. IMPORTANT: Note that a tautomeric shift is not itself a mutation, but a transient change to an alternative form of the molecule.

What is tautomerism discuss its role in DNA bases leading to mutation induction?

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.

How does Tautomerization affect DNA?

In DNA, spontaneous formation of minor tautomers has been speculated to contribute to mutagenic mispairings during DNA replication, whereas in RNA, minor tautomeric forms have been proposed to enhance the structural and functional diversity of RNA enzymes and aptamers.

Is 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 Tautomerization in DNA?

When a tautomeric shift occurs what is true about the resulting mutation?

When a tautomeric shift occurs, what is TRUE about the resulting mutation? 1. The resulting mutation is always corrected by DNA polymerase’s proofreading ability.

What is tautomeric mutation?

The spontaneous isomerization of a nitrogen base to an alternative hydrogen-bonding form, possibly resulting in a mutation. Reversible shifts of proton position in a molecule. bases in nucleic acids shift between keto and enol forms or between amino and imino forms.

Which type of mutation arise due to a tautomeric shift in nitrogenous bases of DNA?

transition mutation –
transition mutation – change of one purine/pyrimidine pair to the other purine/pyrimidine pair. This can happen when one base member of a complementary pair undergoes a tautomeric shift during DNA replication, causing it to mispair.

Which type of mutation leads to a frameshift mutation?

A frameshift mutation is a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read.

Which type of mutation arises due to a tautomeric shift in nitrogenous bases of DNA?

What is a DNA frameshift mutation?

​Frameshift Mutation A frameshift mutation in a gene refers to the insertion or deletion of nucleotide bases in numbers that are not multiples of three. This is important because a cell reads a gene’s code in groups of three bases when making a protein.

What happens to DNA in a frameshift mutation?

If a mutation disrupts this normal reading frame, then the entire gene sequence following the mutation will be incorrectly read. This can result in the addition of the wrong amino acids to the protein and/or the creation of a codon that stops the protein from growing longer.

What is keto enol tautomerism?

Keto-Enol Tautomerism. Keto-Enol Tautomerism is a process where an equilibrium occurs between the keto form (ie a normal-looking ketone) and the enol form (a double bond adjacent to an alcohol) of a carbonyl, acheived through the movement of atoms and breaking of single bonds. Spoiler alert: In most cases, the keto form is highly favored.

Can the keto form of cytosine change to enol form?

However, the keto form occasionally changes spontaneously to the enol form, which has different base-pairing properties. For example, the keto form of cytosine pairs with guanine (its…

What is the keto form of a DNA base?

The keto form of a DNA base is the normal form that gives the molecule its standard base-pairing properties. However, the keto form occasionally changes spontaneously to the enol form, which has different base-pairing properties. For example, the keto form of cytosine pairs with guanine (its…

What are the mechanistic steps of interconversion between keto and enol tautomers?

The following mechanistic steps represent the continuous interconversion between the keto and enol tautomers. In the first step, the carbonyl oxygen is protonated by an acid to form an intermediate oxonium compound. A base removes an α-hydrogen during the second step forming a double bond by an E2 type reaction.