200d
From Proteopedia
STABLE LOOP IN THE CRYSTAL STRUCTURE OF THE INTERCALATED FOUR-STRANDED CYTOSINE-RICH METAZOAN TELOMERE
Overview
In most metazoans, the telomeric cytosine-rich strand repeating sequence is d(TAACCC). The crystal structure of this sequence was solved to 1.9-A resolution. Four strands associate via the cytosine-containing parts to form a four-stranded intercalated structure held together by C.C+ 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' thymine Hoogsteen-base-paired to the third adenine. The 5' end of this loop is in close proximity to the 3' 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.
About this Structure
Full crystallographic information is available from OCA.
Reference
Stable loop in the crystal structure of the intercalated four-stranded cytosine-rich metazoan telomere., Kang C, Berger I, Lockshin C, Ratliff R, Moyzis R, Rich A, Proc Natl Acad Sci U S A. 1995 Apr 25;92(9):3874-8. PMID:7731999 Page seeded by OCA on Sat May 3 18:17:32 2008
Categories: Berger, I. | Kang, C. | Lockshin, C. | Moyzis, R. | Ratliff, R. | Rich, A. | Base intercalated | Loop | Quadruple helix | Tetraplex | U-dna
