BROWSE

Related Researcher

Author's Photo

Lee, Ja Yil
School of Life Sciences
Research Interests
  • Investigated eukaryotic homologous recombination.

ITEM VIEW & DOWNLOAD

Structural diversity and extreme stability of unimolecular Oxytricha nova telomeric G-quadruplex

Cited 0 times inthomson ciCited 0 times inthomson ci
Title
Structural diversity and extreme stability of unimolecular Oxytricha nova telomeric G-quadruplex
Author
Lee, Ja YilYoon, JeongminKihm, Hyun WooKim, D. S.
Issue Date
2008-03
Publisher
AMER CHEMICAL SOC
Citation
BIOCHEMISTRY, v.47, no.11, pp.3389 - 3396
Abstract
Oxytricha nova telomeric DNA contains guanine-rich short-tandem repeat sequences (GGGGTTTT). and terminates as a single strand at the 3'-end. This single-stranded overhang forms a novel DNA structure, namely, G-quadruplex, comprising four quartets. In this study, we investigated the structures and dynamics of unimolecular Oxytricha nova (O. nova) telomeric G-quadruplexes by performing single molecule fluorescence resonance energy transfer (FRET) spectroscopy and bulk circular dichroism (CD) measurements. We observed that unimolecular O. nova G-quadruplexes exhibit structural polymorphism according to monovalent cations. In the presence of Na+, only antiparallel conformation is detected, which was demonstrated in previous studies; however, in the presence of K+, they fold into two different conformations, a parallel conformation and an antiparallel one different from that induced by Na+. Furthermore, these G-quadruplexes show extremely high stability in their dynamics when compared with human G-quadruplexes. While human telomeric G-quadruplexes that possess three quartets display fast dynamic behavior (< 100 s) at low K+ concentrations or high temperatures, O. nova G-quadruplexes maintain their conformational state for a long time (> 1000 s), even at the lowest K+ concentration and the highest temperature investigated. This high stability is primarily due to an extra quartet that results in additional cation coordination. In addition to cation coordination, we propose that other factors such as base stacking and the size of the thymine loop may contribute to the stability of O. nova G-quadruplexes; this is based on the fact that the O. nova G-quadruplexes were observed to be more stable than the human ones in the presence of Li+, which is known to greatly destabilize G-quadruplexes because of imprecise coordination. This extreme stability of four-quartet G-quadruplexes enables telomere protection even in the absence of protective proteins or in the case of abrupt environmental changes, although only a single G-quadruplex structure can be derived from the short single-stranded overhang
URI
Go to Link
DOI
10.1021/bi702013d
ISSN
0006-2960
Appears in Collections:
SLS_Journal Papers
Files in This Item:
2-s2.0-40849116291.pdf Download

find_unist can give you direct access to the published full text of this article. (UNISTARs only)

Show full item record

qrcode

  • mendeley

    citeulike

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

MENU