Anticodonbinding

Anticodonbinding refers to the interaction between the transfer RNA (tRNA) anticodon and the corresponding messenger RNA (mRNA) codon during translation, and, more broadly, to protein domains that recognize tRNA anticodons. In the ribosome, the anticodon loop of a tRNA pairs with the codon in the A site, directing the incorporation of the correct amino acid. Base pairing follows the standard Watson-Crick rules at the first two positions and often permits wobble pairing at the third position, enabling a single tRNA to recognize multiple codons. The decoding center of the ribosome, aided by elongation factors, enforces fidelity through induced-fit binding and kinetic proofreading, reducing misreading and frameshifting. Post-transcriptional modifications of anticodon bases and tRNA structure influence binding strength and codon bias, contributing to translational efficiency and accuracy.

In addition to ribosome-mediated decoding, several aminoacyl-tRNA synthetases contain anticodon-binding domains that recognize the tRNA anticodon during the charging reaction. Anticodon-binding domains help ensure that the correct amino acid is attached to a given tRNA by stabilizing tRNA binding and discriminating among similar tRNA substrates. The presence, structure, and placement of anticodon-binding domains vary among enzyme families and kingdoms, reflecting divergent evolutionary solutions to tRNA recognition. Collectively, anticodon binding is central to translating genetic information into functional proteins and to maintaining translational fidelity.