Stable loop in the crystal structure of the intercalated four-stranded cytosine-rich metazoan telomere
- Massachusetts Institute of Technology, Cambridge, MA (United States); and others
In most metazoans, the telomeric cytosine-rich strand repeating sequence is d(TAACCC). The crystal structure of this sequence was solved to 1.9-{angstrom} resolution. Four strands associate via the cytosine-containing parts to form a four-stranded intercalated structure held together by C-C{sup +} hydrogen bonds. The base-paired strands are parallel to each other, and the two duplexes are intercalated into each other in opposite orientations. One TAA end forms a highly stabilized loop with the 5{prime} thymine Hoogsteen-base-paired to the third adenine. The 5{prime} end of this loop is in close proximity to the 3{prime} end of one of the other intercalated cytosine strands. Instead of being entirely in a DNA duplex, this structure suggests the possibility of an alternative conformation for the cytosine-rich telomere strands. 25 refs., 5 figs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 96325
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Vol. 92, Issue 9; Other Information: PBD: 25 Apr 1995
- Country of Publication:
- United States
- Language:
- English
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