Transiently Misacylated tRNA Is a Primer for Editing of Misactivated Adenylates
Brian E. Nordin and Paul Schimmel
Biochemistry October 18, 2003
Copyright © 2003 American Chemical Society Fidelity in the transduction of biological information stored in the genetic code depends on precise molecular recognition. Aminoacyl-tRNA synthetases initiate this process through the specific attachment of amino acids to the 3'-end of tRNA. The aminoacylation of tRNA occurs in two steps. First, an amino acid and ATP are condensed to give an aminoacyl adenylate. Subsequently, the aminoacyl group is transferred to the 3'-end of the tRNA. While most aminoacyl-tRNA synthetases select their cognate amino acid with high fidelity in the first step of the reaction, both the isoleucyl- and valyl-tRNA synthetases mistakenly activate amino acids that are structurally similar to their cognate amino acids. These two enzymes achieve high fidelity in the overall aminoacylation reaction through secondary editing reactions.
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