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An eight-stranded helical fragment in RNA crystal structure: implications for tetraplex interaction
Baocheng Pan1, Yong Xiong, Ke Shi
1Departments of Chemistry and Biochemistry, The Ohio State University, 200 Johnston Lab, 176 West 19th Avenue, Columbus, OH 43210, USA.
Structure (London, England : 1993)
|July 5, 2003
Summary
This study reveals the crystal structure of a novel nucleic acid octaplex, a complex helical formation. This structure, involving adenine tetrads and uridine interactions, offers insights into nucleic acid structural diversity and function.
Area of Science:
- Structural biology
- Nucleic acid chemistry
- Biochemistry
Background:
- Multistranded helical structures in nucleic acids are crucial for various biological processes.
- Understanding these complex structures is key to deciphering their functional roles.
Purpose of the Study:
- To determine the crystal structure of a novel nucleic acid hexamer, rU(BrdG)r(AGGU).
- To elucidate the structural organization of an eight-stranded helical fragment within a complex of two tetraplexes.
Main Methods:
- X-ray crystallography at 1.5 A resolution.
- Analysis of nucleic acid structural complexes.
Main Results:
- The crystal structure revealed an alternating antiparallel eight-stranded helical fragment sandwiched between two tetraplexes, forming an octaplex.
- The octaplex formation involves groove binding and base tetrad intercalation.
- Adenines formed a novel N6-H em leader N3 conformation base tetrad, interacting with uridines via reverse Hoogsteen pairing to form an adenine-uridine octad.
Conclusions:
- The study presents the first crystal structure of this specific nucleic acid octaplex.
- The conformational flexibility of the adenine tetrad allows for optimized interactions in different biological contexts.
- This finding contributes to understanding the diverse structural motifs and functional capabilities of nucleic acids.