Download MendeleyDNA G-quartets in a 1.86 A resolution structure of an Oxytricha nova telomeric protein-DNA complex.
Horvath, M.P., Schultz, S.C.(2001) J Mol Biol 310: 367-377
- PubMed: 11428895
- DOI: https://doi.org/10.1006/jmbi.2001.4766
- Primary Citation of Related Structures:
1JB7 - PubMed Abstract:
The Oxytricha nova telomere end binding protein (OnTEBP) recognizes, binds and protects the single-stranded 3'-terminal DNA extension found at the ends of macronuclear chromosomes. The structure of this complex shows that the single strand GGGGTTTTGGGG DNA binds in a deep cleft between the two protein subunits of OnTEBP, adopting a non-helical and irregular conformation. In extending the resolution limit of this structure to 1.86 A, we were surprised to find a G-quartet linked dimer of the GGGGTTTTGGGG DNA also packing within the crystal lattice and interacting with the telomere end binding protein. The G-quartet DNA exhibits the same structure and topology as previously observed in solution by NMR with diagonally crossing d(TTTT) loops at either end of the four-stranded helix. Additionally, the crystal structure reveals clearly visible Na(+), and specific patterns of bound water molecules in the four non-equivalent grooves. Although the G-quartet:protein contact surfaces are modest and might simply represent crystal packing interactions, it is interesting to speculate that the two types of telomeric DNA-protein interactions observed here might both be important in telomere biology.
Organizational Affiliation:
Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA. Horvath@biology.utah.edu
