230d
From Proteopedia
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SOLUTION STRUCTURES OF UNIMOLECULAR QUADRUPLEXES FORMED BY OLIGONUCLEOTIDES CONTAINING OXYTRICHA TELOMERE REPEATS
Overview
BACKGROUND: Oligonucleotides containing the guanine-rich telomeric, sequence of Oxytricha chromosomes (dT4G4) have previously been shown to, form DNA quadruplexes comprising guanine quartets stabilized by cations., Two different structures have been reported for both d(G4T4G4) (Oxy1.5), and d(G4T4G4T4G4T4G4) (Oxy3.5). RESULTS: Here we present the solution, structure of a uracil- and inosine-containing derivative of Oxy3.5, d(G4TUTUG4T4G4UUTTG3I) (Oxy3.5-U4128), determined using two-dimensional 1H, and 31P NMR techniques. This oligonucleotide forms a unimolecular, quadruplex that is very similar to the dimeric Oxy1.5 solution structure, in that it contains a loop spanning the diagonal of an end quartet. The, groove widths, strand polarities, and positions of the syn bases along the, G4 tracts and within the quartets are all as reported for Oxy1.5. The, first and third pyrimidine tracts form parallel loops spanning a wide, groove and a narrow groove respectively. CONCLUSIONS: Both Oxy3.5 and, Oxy3.5-U(4)128 form unimolecular quadruplexes in solution with a diagonal, central T4 loop. These results conflict with those reported for, d(G4TUTUG4TTUUG4UUTTG4) in solution, in which the central loop spans a, wide groove.
About this Structure
230D is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Solution structures of unimolecular quadruplexes formed by oligonucleotides containing Oxytricha telomere repeats., Smith FW, Schultze P, Feigon J, Structure. 1995 Oct 15;3(10):997-1008. PMID:8590010
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