1JB7

DNA G-Quartets in a 1.86 A Resolution Structure of an Oxytricha nova Telomeric Protein-DNA Complex

Summary for 1JB7

• Entry DOI: 10.2210/pdb1jb7/pdb
• Related: 156d 1otc
• Descriptor: 5'-D(*GP*GP*GP*GP*TP*TP*TP*TP*GP*GP*GP*G)-3', telomere-binding protein alpha subunit, telomere-binding protein beta subunit, ... (6 entities in total)
• Functional Keywords: telomere-binding protein, dna-protein interactions, dna hydration, sodium ion, quadruplex dna, dna-binding protein-dna complex, dna-binding protein/dna
• Biological source: Sterkiella nova; More
• Cellular location: Nucleus: P29549 P16458
• Total number of polymer chains: 5
• Total formula weight: 96428.77

Authors

Horvath, M.P.,Schultz, S.C. (deposition date: 2001-06-02, release date: 2001-06-11, Last modification date: 2023-08-16)

Primary citation

Horvath, M.P.,Schultz, S.C.
DNA G-quartets in a 1.86 A resolution structure of an Oxytricha nova telomeric protein-DNA complex.
J.Mol.Biol., 310:367-377, 2001

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.

PubMed: 11428895
DOI: 10.1006/jmbi.2001.4766

Experimental method

X-RAY DIFFRACTION (1.86 Å)