Reproducing the three-dimensional structure of a tRNA molecule from structural constraints

Area of Science:

• Structural biology
• Computational biology
• RNA structure and function

Background:

• Transfer RNA (tRNA) is essential for protein synthesis, and understanding its three-dimensional structure is crucial.
• Previous knowledge of tRNA secondary structure and some tertiary interactions informed computational modeling efforts.

Purpose of the Study:

• To reproduce the atomic-resolution three-dimensional structure of yeast tRNA(Phe) using an automated RNA modeling program.
• To investigate the role of specific structural constraints, particularly tertiary base pairs, in accurate RNA modeling.

Main Methods:

• Utilized the automated RNA modeling program MC-SYM, which employs a constraint-satisfaction algorithm.
• Incorporated structural constraints derived from secondary structure and known tertiary base pairs.
• Evaluated generated models against the experimentally determined x-ray crystal structure.

Main Results:

• Successfully reproduced the yeast tRNA(Phe) structure at atomic resolution, generating 26 valid models.
• All models exhibited the canonical "L" shape characteristic of tRNA.
• Root-mean-square deviations from the crystal structure ranged from 3.1 to 3.8 Å.
• Identified the interaction between uridine-8 and adenosine-14 as both necessary and sufficient for forming the tRNA L-shape.

Conclusions:

• The MC-SYM program effectively models RNA tertiary structures using a constraint-satisfaction approach.
• Specific tertiary interactions play a critical role in dictating the overall three-dimensional fold of tRNA.
• The interaction between U8 and A14 is a key determinant of the tRNA L-shaped conformation.