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Structure of the unusual seryl-tRNA synthetase reveals a distinct
zinc-dependent mode of substrate recognition
JournalArticle (Originalarbeit in einer wissenschaftlichen Zeitschrift)
ID 755157
Author(s) Bilokapic, S.; Maier, T.; Ahel, D.; Gruic-Sovulj, I.; Soll, D.; Weygand-Durasevic, I.; Ban, N.
Author(s) at UniBasel Maier, Timm;
Year 2006
Title Structure of the unusual seryl-tRNA synthetase reveals a distinct zinc-dependent mode of substrate
recognition
Journal Embo Journal
Volume 25
Number 11
Pages / Article-Number 2498-2509
Methanogenic archaea possess unusual seryl-tRNA synthetase ( SerRS), evolutionarily distinct from the
SerRSs found in other archaea, eucaryotes and bacteria. The two types of SerRSs show only minimal
sequence similarity, primarily within class II conserved motifs 1, 2 and 3. Here, we report a 2.5 angstrom
resolution crystal structure of the atypical methanogenic Methanosarcina barkeri SerRS and its complexes
with ATP, serine and the non-hydrolysable seryl-adenylate analogue 5`-O-(N-serylsulfamoyl) adenosine. The
structures reveal two idiosyncratic features of methanogenic SerRSs: a novel N-terminal tRNA-binding domain
and an active site zinc ion. The tetra-coordinated Zn2+ ion is bound to three conserved protein ligands (
Cys306, Glu355 and Cys461) and binds the amino group of the serine substrate. The absolute requirement of
the metal ion for enzymatic activity was confirmed by mutational analysis of the direct zinc ion ligands. This
zinc-dependent serine recognition mechanism differs fundamentally from the one employed by the bacterialtype SerRSs. Consequently, SerRS represents the only known aminoacyl-tRNA synthetase system that
evolved two distinct mechanisms for the recognition of the same amino-acid substrate.
ISSN/ISBN 0261-4189
Full Text on edoc
Digital Object Identifier DOI 10.1038/sj.emboj.7601129
Document type (ISI) article