page_title: Hoogsteen base pair
section_title: Triplex structures
hierarchical_section_title: Hoogsteen base pair / Triplex structures
caption_attribution_description: English: Base triads in a DNA triple helix structure. In each triad the base shown on the top left forms Hoogsteen hydrogen bonds with the base in the middle. The triads are grouped according to whether they form a triplex of the form YR*Y or YR*R ((Y is a pyrimidine, R is a purine, * is a Hoogsteen pairing). The arrow diagrams on the right indicate the direction and types of the strands forming YR*Y and YR*R triplexes&#160;: thick vertical lines, Watson-Crick base pairs; dashed vertical lines, Hoogsteen hydrogen base pairs; solid arrows, purine strands; dashed arrows, pyrimidine strands. ERROR: TAT AND TAA are labelled wrong/backwards. Figure based on Frank-Kamenetskii and Mirkin (1995) Ann. Rev of Biochem. 64:65-95, drawn with ChemBioDraw Ultra. Türkçe: DNA üçlü sarmal yapısında baz üçlüleri. Her üçlüde, yukarı solda gösterilen baz, ortadaki baz ile Hoogsteen hidrojen bağları oluşturmaktadır. Üçlüler, YR*Y veya YR*R tipi olduklarına göre gruplandırılmıştır (Y bir pürin, R bir pirimidin, * Hogsteen bağlanmasıdır). Sağdaki oklu şekiller, YR*Y ve YR*R tipi üçlülerde iplikçiklerin yönü ve tipini belirtir: kalın dikey çizgiler, Watson-Crick hidrojen baz çiftleri, kesikli dikey çizgiler Hoogsteen baz çiftleri, düz oklar pürin iplikçikleri, kesikli oklar pirimidin iplikçikleri. Kaynak: Frank-Kamenetskii &amp; Mirkin (1995) Ann. Rev of Biochem. 64:65-95. ChemBioDraw Ultra yazılımı ile çizilmiştir.
context_page_description: A Hoogsteen base pair is a variation of base-pairing in nucleic acids such as the A•T pair. In this manner, two nucleobases, one on each strand, can be held together by hydrogen bonds in the major groove. A Hoogsteen base pair applies the N7 position of the purine base and C6 amino group, which bind the Watson-Crick face of the pyrimidine base.
context_section_description: This non-Watson-Crick base-pairing allows the third strands to wind around the duplexes, which are assembled in the Watson-Crick pattern, and form triple-stranded helices such as (poly(dA)•2poly(dT)) and (poly(rG)•2poly(rC)). It can be also seen in three-dimensional structures of transfer RNA, as T54•A58 and U8•A14.
caption: Base triads in a DNA triple helix structure.
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