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Solution structure of a tRNA with a large variable region: yeast tRNASer
A C Dock-Bregeon1, E Westhof, R Giegé
1Laboratoires de Biochimie et de Cristallographie Biologique Institut de Biologie Moléculaire et Cellulaire du C.N.R.S., Strasbourg, France.
Journal of Molecular Biology
|April 20, 1989
Summary
This study used chemical reagents to map the yeast tRNASer tertiary structure, revealing details of its large variable region and confirming its structural model. The findings provide insights into tRNA folding and can be generalized to other tRNAs.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Transfer RNAs (tRNAs) are crucial for protein synthesis, translating genetic code.
- Yeast tRNASer possesses a large variable region, posing unique structural challenges.
- Understanding tRNA tertiary structure is key to deciphering its function and regulation.
Purpose of the Study:
- To elucidate the tertiary structure of yeast tRNASer, particularly its large variable region.
- To map chemically reactive sites and protected regions within the tRNA molecule.
- To build and refine a structural model based on experimental data.
Main Methods:
- Chemical modification using ethylnitrosourea, dimethylsulphate, and diethylpyrocarbonate.
- Analysis of reactivity and protection patterns of specific nucleotide bases and phosphate groups.
- 3D model building and refinement using a PS300 graphic system.
Main Results:
- Confirmed the presence of a four base-pair variable stem and a three-residue variable loop.
- Identified accessible and protected N-7 positions in purines, indicating tertiary folding.
- Detected strong phosphate protection in specific regions, further defining the structure.
- Developed a refined structural model for yeast tRNASer with an accessible variable arm.
Conclusions:
- The study successfully mapped the tertiary structure of yeast tRNASer using chemical probing.
- The refined model provides a detailed view of tRNA folding, accommodating a large variable region.
- The findings offer a framework for understanding similar structures in other tRNAs.