Structural Insights into the Polyphyletic Origins of Glycyl tRNA Synthetases
Journal article, 2016

Glycyl tRNA synthetase (GlyRS) provides a unique case among class II aminoacyl tRNA synthetases, with two clearly widespread types of enzymes: a dimeric ((2)) species present in some bacteria, archaea, and eukaryotes; and a heterotetrameric form ((22)) present in most bacteria. Although the differences between both types of GlyRS at the anticodon binding domain level are evident, the extent and implications of the variations in the catalytic domain have not been described, and it is unclear whether the mechanism of amino acid recognition is also dissimilar. Here, we show that the -subunit of the (22) GlyRS from the bacterium Aquifex aeolicus is able to perform the first step of the aminoacylation reaction, which involves the activation of the amino acid with ATP. The crystal structure of the -subunit in the complex with an analog of glycyl adenylate at 2.8 angstrom resolution presents a conformational arrangement that properly positions the cognate amino acid. This work shows that glycine is recognized by a subset of different residues in the two types of GlyRS. A structural and sequence analysis of class II catalytic domains shows that bacterial GlyRS is closely related to alanyl tRNA synthetase, which led us to define a new subclassification of these ancient enzymes and to propose an evolutionary path of (22) GlyRS, convergent with (2) GlyRS and divergent from AlaRS, thus providing a possible explanation for the puzzling existence of two proteins sharing the same fold and function but not a common ancestor.

protein structures

alpha-subunit

aminoacyl tRNA synthetase

escherichia-coli

sequence alignment

acceptor-stem

ribonucleic-acid synthetase

thermus-thermophilus

crystal structure

beta-subunit

horizontal gene-transfer

crystal-structure

substrate

structure-function

molecular evolution

Author

M. I. Valencia-Sanchez

A. Rodriguez-Hernandez

Ruben Ferreira

University of Gothenburg

H. A. Santamaria-Suarez

M. Arciniega

A. C. Dock-Bregeon

D. Moras

B. Beinsteiner

H. Mertens

D. Svergun

L. G. Brieba

Morten Grötli

University of Gothenburg

A. Torres-Larios

Journal of Biological Chemistry

0021-9258 (ISSN) 1083-351X (eISSN)

Vol. 291 28 14430-14446

Subject Categories

Cell and Molecular Biology

DOI

10.1074/jbc.M116.730382

More information

Latest update

4/18/2018