Hydrolysis of non-cognate aminoacyl-adenylates by a class II aminoacyl-tRNA synthetase lacking an editing domain.

Ita Gruic-Sovulj, Jasmina Rokov-Plavec, Ivana Weygand-Durasevic

Index: FEBS Lett. 581(26) , 5110-4, (2007)

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Abstract

Aminoacyl-tRNA synthetases, a group of enzymes catalyzing aminoacyl-tRNA formation, may possess inherent editing activity to clear mistakes arising through the selection of non-cognate amino acid. It is generally assumed that both editing substrates, non-cognate aminoacyl-adenylate and misacylated tRNA, are hydrolyzed at the same editing domain, distant from the active site. Here, we present the first example of an aminoacyl-tRNA synthetase (seryl-tRNA synthetase) that naturally lacks an editing domain, but possesses a hydrolytic activity toward non-cognate aminoacyl-adenylates. Our data reveal that tRNA-independent pre-transfer editing may proceed within the enzyme active site without shuttling the non-cognate aminoacyl-adenylate intermediate to the remote editing site.