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Updated: Jul 22, 2026
11:42
Iterative Optimization of DNA Duplexes for Crystallization of SeqA-DNA Complexes
Published on: November 1, 2012
Crystal structure of four-stranded Oxytricha telomeric DNA
1Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Nature
|March 12, 1992
Summary
Oxytricha telomere DNA forms a stable four-stranded helical structure. This structure, crucial for chromosome stability, exhibits inherent flexibility due to its unique guanine and thymine arrangements.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Telomeres protect chromosome ends from degradation.
- The Oxytricha telomere sequence contains a G-rich overhang.
- Understanding telomere structure is key to cellular aging and cancer research.
Purpose of the Study:
- To determine the three-dimensional structure of the Oxytricha telomere sequence d(GGGGTTTTGGGG).
- To elucidate the molecular interactions stabilizing the telomeric DNA structure.
Main Methods:
- Crystallization of the oligonucleotide sequence.
- X-ray diffraction to solve the three-dimensional structure at 2.5 A resolution.
Main Results:
- The DNA sequence forms hairpin structures that associate into a four-stranded helix.
- Guanine residues form cyclic hydrogen bonds, with an ion at the center.
- Thymine residues form loops at the ends of the structure.
- The structure contains two four-stranded molecules, indicating intrinsic flexibility.
Conclusions:
- The Oxytricha telomere sequence adopts a stable, four-stranded helical conformation.
- The observed structure provides insights into telomere maintenance and stability.
- The inherent flexibility may play a role in telomere function.
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