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| QUADRUPLEX STRUCTURE OF OXYTRICHA TELOMERIC DNA OLIGONUCLEOTIDES |
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| Author(s): SMITH FW, FEIGON J |
| Source: NATURE Volume: 356 Issue: 6365 Pages: 164-168 Published: MAR 12 1992 |
| Times Cited: 378 References: 27 |
| Abstract: THE telomeres of most eukaryotes contain a repeating G-rich sequence with the consensus d(T/A)1-4G1-8, of which 12-16 bases form a 3' single-strand overhang beyond the telomeric duplex 1. It has been proposed that these G-rich oligonucleotides associate to form four-stranded structures from one 2-4, two 2,5 or four 6,7 individual strands and that these structures may be relevant in vivo. The proposed structures contain Hoogsteen base-paired G-quartets, precedent for which has been in the literature for many years 8. Here we use H-1 NMR spectroscopy to study the conformations of the DNA oligonucleotides d(G4T4G4) (Oxy-1.5) and d(G4T4G4T4G4T4G4) (Oxy-3.5) which contain the Oxytricha telomere repeat (T4G4). We find that these molecules fold to form a symmetrical bimolecular and an intramolecular quadruplex, respectively. Both structures have four G-quartets formed from nucleotides that are alternately syn and anti along each strand. This arrangement differs from earlier models in which the strands are alternately all syn or all anti 2,3,5 . The T4 loops in Oxy-1.5 are on opposite ends of the quadruplex and loop diagonally across the G-quartet, resulting in adjacent strands being alternately parallel and antiparallel. |
| Document Type: Article |
| Language: English |
Addresses:
1. UNIV CALIF LOS ANGELES, DEPT CHEM & BIOCHEM, LOS ANGELES, CA 90024 USA
2. UNIV CALIF LOS ANGELES, INST MOLEC BIOL, LOS ANGELES, CA 90024 USA |
| Publisher: MACMILLAN MAGAZINES LTD, PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW |
| Subject Category: Multidisciplinary Sciences |
| IDS Number: HH731 |
| ISSN: 0028-0836 |
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