A WHEP Domain Regulates the Dynamic Structure and Activity of Caenorhabditis elegans Glycyl-tRNA Synthetase.
WHEP domains exist in certain eukaryotic aminoacyl-tRNA synthetases and play roles in tRNA or protein binding. We present evidence herein that cytoplasmic and mitochondrial forms of Caenorhabditis elegans glycyl-tRNA synthetase (CeGlyRS) are encoded by the same gene (CeGRS1) through alternative initiation of translation. The cytoplasmic form possessed an N-terminal WHEP domain, whereas its mitochondrial isoform possessed an extra N-terminal sequence consisting of an mitochondrial targeting signal and an appended domain. Cross-species complementation assays showed that CeGRS1 effectively rescued the cytoplasmic and mitochondrial defects of a yeast GRS1 knock-out strain. Although both forms of CeGlyRS efficiently charged the cytoplasmic tRNAs(Gly) of C. elegans, the mitochondrial form was much more efficient than its cytoplasmic counterpart in charging the mitochondrial tRNA(Gly) isoacceptor, which carries a defective TψC hairpin. Despite the WHEP domain per se lacking tRNA binding activity, deletion of this domain reduced the catalytic efficiency of the enzyme. Most interestingly, the deletion mutant possessed a higher thermal stability and a somewhat lower structural flexibility. Our study suggests a role for the WHEP domain as a regulator of the dynamic structure and activity of the enzyme.
From the Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan.
Chih-Yao
0000-0002-6688-1520
CY
Chang
From the Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan.
Chin-I
0000-0002-6073-2532
CI
Chien
From the Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan.
Chia-Pei
0000-0002-1412-9652
CP
Chang
From the Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan.
Bo-Chun
BC
Lin
From the Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan dukewang@cc.ncu.edu.tw.
Chien-Chia
0000-0002-7104-1307
CC
Wang
D000818:Animals; D017173:Caenorhabditis elegans / Q000201:enzymology* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006032:Glycine-tRNA Ligase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000072417:Protein Domains; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; C478769:GRS1 protein, S cerevisiae; D006032:Glycine-tRNA Ligase
Caenorhabditis elegans (C. elegans); aminoacyl tRNA synthetase; neurodegenerative disease; neurological disease; protein domain; protein synthesis