Question

Describe your understanding of a Hoogsteen pair and the formation of nucleic acid triplex. Is this held together by an intermolecular bond or an intramolecular bond? 

Answer 1

• A Hoogsteen pair is a pair of nucleotides that is formed according to the principle of complementarity, but at the same time, one of the nucleotides is rotated 180 degrees in such a way that this nucleotide is synonymous and hydrogen bonds are formed according to a different principle. At the same time, between guanine and cytosine 2 hydrogen bonds were found. It is held together by an intramolecular bond.
• The triplex structure of DNA is formed when a portion of a short single-stranded nucleic acid is attached to the major groove of double-stranded DNA. If nucleotide pairs in DNA are formed according to the Watson-Crick principle, then individual nucleotides of the external nucleic acid, forming a hydrogen bond with DNA nucleotides, form Hoogsteen pairs. It is held together by an intermolecular bond.