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New wrinkles on polynucleotide duplexes
S Arnott1, R Chandrasekaran, A K Banerjee
1Department of Biological Sciences, Purdue University, West Lafayette, IN 47907.
Journal of Biomolecular Structure & Dynamics
|October 1, 1983
Summary
Polynucleotides can form complex secondary structures beyond simple helices, including exotic pleiomeric DNA with large, varied nucleotide conformations. These structures reveal new insights into DNA
Area of Science:
- Molecular Biology
- Biophysics
- Structural Biology
Background:
- Most polynucleotides form regular helical secondary structures based on single nucleotide motifs.
- Isomorphous base pairing (A:T, G:C) and dyadically-related glycosylic bonds facilitate these regular structures.
Purpose of the Study:
- To investigate and describe polynucleotide secondary structures with larger, more complex repeating motifs.
- To introduce and define the term "pleiomeric DNA" for structures with large asymmetric units and varied nucleotide conformations.
Main Methods:
- Analysis of polynucleotide sequences and their corresponding secondary structures.
- Characterization of exotic DNA forms, such as the tetragonal form of poly d(AT):poly d(AT).
Main Results:
- Polynucleotides can adopt secondary structures with larger motifs, reflecting their base sequences (e.g., Z-like forms, wrinkled B and D forms).
- Exotic structures like a tetragonal form of poly d(AT):poly d(AT) exhibit large unit cells and complex helical arrangements.
- The term "pleiomeric DNA" is proposed for structures with large asymmetric units and diverse nucleotide conformations.
Conclusions:
- The diversity of polynucleotide secondary structures extends beyond simple helices.
- Pleiomeric DNA structures accommodate varied nucleotide conformations, offering new models for DNA organization.
- Understanding these complex structures is crucial for comprehending DNA's functional versatility.