tRNA Structure Explorer
Click any region of the tRNA to learn about it
Cloverleaf (2D)
L-shape (3D)
Region Guide
Acceptor stem
— 7 bp, 3' CCA end (aminoacylation site)
D-loop
— dihydrouridine (D); binds EF-Tu, synthetases
Anticodon loop
— 7 nt; anticodon triplet decodes mRNA
TΨC loop
— pseudouridine (Ψ); contacts ribosome 50S
Variable loop
— 3–5 nt (class I) or up to 21 nt (class II)
Click a region
Hover or click any highlighted region on the tRNA diagram to see detailed functional information.
Aminoacyl-tRNA Synthetases
20 aaRS enzymes, one per amino acid. They recognize tRNA identity elements:
• Discriminator base (position 73)
• Anticodon bases
• Acceptor stem sequence
• D-loop / variable loop features
Two classes
: Class I (Rossmann fold, attach AA to 2'-OH) and Class II (unique fold, 3'-OH). Error rate ~1:10,000 — proofreading by editing domain.