What the difference between Thymine and Uracil?

TL;DR

This paper explores the chemical differences between thymine and uracil, focusing on their keto and enol forms and how methylation influences their pairing behaviors in nucleic acids.

Contribution

It provides a detailed analysis of the structural and chemical distinctions between thymine and uracil, emphasizing the role of methylation and tautomeric forms in base pairing.

Findings

Thymine exists only in keto form and pairs with adenine.

Uracil can adopt enol form, enabling U-G pairing.

Methylation stabilizes uracil in keto form, affecting pairing preferences.

Abstract

The wobble hypothesis does not discriminate between uracil and thymine. Methylation could favor further stabilization of uracil in the keto form. Thymine is present in keto form only and can pair up but with adenine. Uracil can easily construct the enol form; that is why it forms the U-G pair.