Tautomeric shift........?

Question

is it caused by migration of hydrogen betweennucleotides resulting in wrong base pair?

is the tautomer partner a=c t=g standard??

Answer 1

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.

Base substitutions are generally caused by changes in the way that nucleotides base pair. One way this occurs is through tautomeric shifts. The chemical nature of the bases of DNA is such that rare but natural, spontaneous fluctuations in the bonds of the bases can occur. These fluctuations can briefly affect the way a base forms hydrogen bonds. For example, adenine, when it undergoes a tautomeric shift, will base pair with cytosine. Therefore, if a tautomeric shift occurs during replication, the wrong nucleotide can be inserted in the newly-synthesized DNA. The bases usually switch back to their normal form quickly, but by that time, it might be too late.

A tautomeric shift produces a transition mutation in complementary strand