tRNA tertiary structure — Which statements about the 3D architecture of yeast tRNA (and most tRNAs) are accurate?

Introduction:
tRNAs adopt a conserved tertiary architecture that enables precise positioning in the ribosome during translation. Yeast tRNA was among the first solved RNA 3D structures and serves as a model for tRNA folding principles.

Given Data / Assumptions:

• tRNAs fold into an L-shaped 3D structure from a cloverleaf secondary structure.
• Stacking and noncanonical base pairs contribute substantially to stability.
• Tertiary interactions bridge distant loops and stems.

Concept / Approach:
Evaluate each statement against known structural features: base stacking, conserved L-shape across tRNAs, and many non–Watson–Crick interactions (e.g., G•U wobble, base triples) that maintain the compact fold and correct geometry for ribosomal binding.

Step-by-Step Solution:

Verification / Alternative check:
X-ray and cryo-EM data of multiple tRNAs and tRNA–ribosome complexes confirm all three features consistently.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming only Watson–Crick pairing matters; overlooking stacking and tertiary contacts in RNA folding.

Final Answer:
All of the above.