Download MendeleyCrystal structures of a DNA octaplex with I-motif of G-quartets and its splitting into two quadruplexes suggest a folding mechanism of eight tandem repeats
Kondo, J., Adachi, W., Umeda, S., Sunami, T., Takenaka, A.(2004) Nucleic Acids Res 32: 2541-2549
- PubMed: 15133122
- DOI: https://doi.org/10.1093/nar/gkh575
- Primary Citation of Related Structures:
1V3N, 1V3O, 1V3P - PubMed Abstract:
Recent genomic analyses revealed many kinds of tandem repeats of specific sequences. Some of them are related to genetic diseases, but their biological functions and structures are still unknown. Two X-ray structures of a short DNA fragment d(gcGA[G]1Agc) show that four base-intercalated duplexes are assembled to form an octaplex at a low K+ concentration, in which the eight G5 residues form a stacked double G-quartet in the central part. At a higher K+ concentration, however, the octaplex is split into just two halves. These structural features suggest a folding process of eight tandem repeats of d(ccGA[G]4Agg), according to a double Greek-key motif. Such a packaging of the repeats could facilitate slippage of a certain sequence during DNA replication, to induce increase or decrease of the repeats.
Organizational Affiliation:
Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
