Original scientific paper

https://doi.org/10.5562/cca1823

Pre-transfer Editing of Serine Hydroxamate within the Active Site of Methanogenic-type Seryl-tRNA Synthetase

Ita Gruić-Sovulj ; Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia
Morana Dulić ; Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia
Ivana Weygand-Đurašević ; Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia

Abstract

Aminoacyl-tRNA synthetases (aaRSs) maintain fidelity of protein synthesis by matching only
cognate amino acid-tRNA pairs. Aminoacylation occurs through activation of amino acid to yield aminoacyl-
adenylate followed by transfer of acyl-moiety to tRNA. Error-prone aaRSs achieve high level of
accuracy using inherent hydrolytic activities towards noncognate aminoacyl-adenylate or misacylated
tRNA (pre- and post-transfer editing).
Seryl-tRNA synthetases can be divided into two structurally different types: canonical and methanogenic-
type. Both types have been shown to efficiently activate serine analogue serine hydroxamate
(SerHX). Moreover, this analogue has been also eliminated by pre-transfer editing within the canonical
synthetic site of yeast SerRS. Here we show that methanogenic-type SerRS from Methanosarcina barkeri
clears misactivated SerHX similarly as the yeast enzyme: SerHX-adenylate is not expelled into solution,
but is enzymatically hydrolyzed in a tRNA-independent manner. Since the enzyme lacks domain specialized
in editing, this shows that methanogenic-type catalytic core is also capable to perform pre-transfer
editing. (doi: 10.5562/cca1823)

Keywords

editing; proofreading; serine hydroxamate; seryl-tRNA synthetase

Hrčak ID:

71980

URI

https://hrcak.srce.hr/71980

Publication date:

3.10.2011.

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