NMR Structures of (rGCUGAGGCU)2 and (rGCGGAUGCU)2: Probing the Structural Features That Shape the Thermodynamic Stability of GA Pairs
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- 作者：Blanton S. Tolbert ; Scott D. Kennedy ; Susan J. Schroeder ; Thomas R. Krugh ; Douglas H. Turner
- 刊名：Biochemistry
- 出版年：2007
- 出版时间：February 13, 2007
- 年：2007
- 卷：46
- 期：6
- 页码：1511 - 1522
- 全文大小：815K
- 年卷期：v.46,no.6(February 13, 2007)
- ISSN：1520-4995
文摘
The NMR structures of 
and 
are reported. The internal loop, 
, is about 2 kcal/mol more stable than 
at 37 
C. The duplexes assemble into similar globalfolds characterized by the formation of tandem sheared GA pairs. The different stabilities of the loops areaccompained by differences in the local structure of the closing GU pairs. In the 
internal loop,the GU pairs form canonical wobble configurations with two hydrogen bonds, whereas in 
, theGU pairs form a single hydrogen bond involving the amino group, GH22, and the carbonyl group, UO4.This pairing is similar to the GU closing pair of the 690 hairpin loop found in E. coli 16S rRNA. The
and 
structures reveal how the subtle interplay between stacking and hydrogen bondingdetermines sequence dependent conformation and thermodynamic stability. Thus, this work providesstructural and thermodynamic benchmarks for theoreticians in the ongoing effort to understand the sequencedependence of RNA physicochemical properties.
and are reported. The internal loop, , is about 2 kcal/mol more stable than at 37 C. The duplexes assemble into similar globalfolds characterized by the formation of tandem sheared GA pairs. The different stabilities of the loops areaccompained by differences in the local structure of the closing GU pairs. In the internal loop,the GU pairs form canonical wobble configurations with two hydrogen bonds, whereas in , theGU pairs form a single hydrogen bond involving the amino group, GH22, and the carbonyl group, UO4.This pairing is similar to the GU closing pair of the 690 hairpin loop found in E. coli 16S rRNA. The and structures reveal how the subtle interplay between stacking and hydrogen bondingdetermines sequence dependent conformation and thermodynamic stability. Thus, this work providesstructural and thermodynamic benchmarks for theoreticians in the ongoing effort to understand the sequencedependence of RNA physicochemical properties.