Non-canonical base pairing

rdf:langString Non-canonical base pairing

rdf:langString Non-canonical base pairing occurs when nucleobases hydrogen bond, or base pair, to one another in schemes other than the standard Watson-Crick base pairs (which are adenine (A) -- thymine (T) in DNA, adenine (A) -- uracil (U) in RNA, and guanine (G) -- cytosine (C) in both DNA and RNA). There are three main types of non-canonical base pairs: those stabilized by polar hydrogen bonds, those having interactions among C−H and O/N groups, and those that have hydrogen bonds between the bases themselves. The first discovered non-canonical base pairs are Hoogsteen base pairs, which were first described by American biochemist Karst Hoogsteen. Non-canonical base pairings commonly occur in the secondary structure of RNA (e.g. pairing of G with U), and in tRNA recognition. They are typically less stable than standard base pairings. The presence of non-canonical base pairs in double stranded DNA results in a disrupted double helix.