Base pairing

Base Pairing is a fundamental principle in the structure of DNA and RNA molecules. It refers to the specific association between nucleotides in these molecules through hydrogen bonds.

Overview

In DNA, base pairing occurs between a purine and a pyrimidine; specifically, adenine pairs with thymine (A-T), and guanine pairs with cytosine (G-C). In RNA, thymine is replaced by uracil (U), so the pairs become A-U and G-C. This specific base pairing forms the basis of nearly all DNA and RNA functions, including DNA replication, transcription, and translation.

Watson-Crick Base Pairing

The concept of base pairing was first proposed by James Watson and Francis Crick in 1953. They suggested that DNA is a double helix, with the two strands held together by hydrogen bonds between the bases. This is now known as Watson-Crick base pairing.

Wobble Base Pairing

In addition to the standard Watson-Crick base pairing, there are also instances of non-standard or "wobble" base pairing. This occurs primarily in RNA, during the process of translation. Wobble base pairing allows for more flexibility in the pairing between the third base of the codon and the first base of the anticodon.

Hoogsteen Base Pairing

Another form of non-standard base pairing is Hoogsteen base pairing, named after Karst Hoogsteen. This involves a different orientation of the bases, allowing for the formation of triple-stranded DNA structures.

Significance

Base pairing is crucial for the preservation of genetic information, as it ensures that DNA can be accurately replicated. It also allows for the transfer of this information from DNA to RNA, and from RNA into protein sequences.

See Also

• Nucleic acid double helix
• DNA replication
• Transcription (genetics)
• Translation (biology)