Journal Article

FZJ-2018-06072

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Structural control of caspase-generated glutamyl-tRNA synthetase by appended noncatalytic WHEP domains

Halawani, D. ; Gogonea, V. ; DiDonato, J. A. ; Pipich, V.FZJ* ; Yao, P. ; China, A. ; Topbas, C. ; Vasu, K. ; Arif, A. ; Hazen, S. L. ; Fox, P. L. (Corresponding author)

2018
Soc.72889 Bethesda, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/20157  doi:10.1074/jbc.M117.807503

Abstract: Aminoacyl-tRNA synthetases are ubiquitous, evolutionarilyconserved enzymes catalyzing the conjugation of amino acidsonto cognate tRNAs. During eukaryotic evolution, tRNA syn-thetases have been the targets of persistent structural modifica-tions. These modifications can be additive, as in the evolution-ary acquisition of noncatalytic domains, or subtractive, as in thegeneration of truncated variants through regulated mechanismssuch as proteolytic processing, alternative splicing, or codingregion polyadenylation. A unique variant is the human glu-tamyl-prolyl-tRNA synthetase (EPRS) consisting of two fusedsynthetases joined by a linker containing three copies of theWHEP domain (termed by its presence in tryptophanyl-, histi-dyl-, and glutamyl-prolyl-tRNA synthetases). Here, we identifysite-selective proteolysis as a mechanism that severs the linkagebetween the EPRS synthetases in vitro and in vivo. Caspaseaction targeted Asp-929 in the third WHEP domain, therebyseparating the two synthetases. Using a neoepitope antibodydirected against the newly exposed C terminus, we demonstrateEPRS cleavage at Asp-929 in vitro and in vivo. Biochemical andbiophysical characterizations of the N-terminally generatedEPRS proteoform containing the glutamyl-tRNA synthetaseand most of the linker, including two WHEP domains, com-bined with structural analysis by small-angle neutron scattering,revealed a role for the WHEP domains in modulating conforma-tions of the catalytic core and GSH–S-transferase–C-terminal-like (GST-C) domain. WHEP-driven conformational rearrange-ment altered GST–C domain interactions and conferreddistinct oligomeric states in solution. Collectively, our resultsreveal long-range conformational changes imposed by theWHEP domains and illustrate how noncatalytic domains canmodulate the global structure of tRNA synthetases in complexeukaryotic systems.

Keyword(s): Polymers, Soft Nano Particles and Proteins (1st) ; Biology (2nd)

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS-FRM-II)
2. Neutronenstreuung (Neutronenstreuung ; JCNS-1)

Research Program(s):

1. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)
2. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)

Experiment(s):

1. KWS-1: Small angle scattering diffractometer (NL3b)

Appears in the scientific report 2018

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Database coverage:
; ; BIOSIS Previews ; Clarivate Analytics Master Journal List ; Current Contents - Life Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; PubMed Central ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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