Dataset Information

On the mechanism and origin of isoleucyl-tRNA synthetase editing against norvaline

ABSTRACT: Aminoacyl-tRNA synthetases (aaRSs), the enzymes responsible for coupling tRNAs to their cognate amino acids, minimize translational errors by intrinsic hydrolytic editing. Here, we compared the propensity of norvaline (Nva), a linear amino acid not coded for protein synthesis, to the proteinogenic, branched valine (Val) to mistranslate isoleucine (Ile) in proteins. We show that in the synthetic site of isoleucyl-tRNA synthetase (IleRS), aminoacylation and pre-transfer editing with Nva and Val occur at similar rates. Post-transfer editing was, however, more efficient with Nva as IleRS misaminoacylates Nva-tRNAIle at slower rate than Val-tRNAIle. Accordingly, an Escherichia coli strain lacking IleRS post-transfer editing misincorporated Nva and Val in the proteome to a similar extent and at the same Ile positions. However, Nva mistranslation inflicted higher toxicity than Val, in agreement with IleRS post-transfer editing domain being optimized for hydrolysis of Nva-tRNAIle. Furthermore, we found that the evolutionary related IleRS, leucyl- and valyl-tRNA synthetases (I/L/VRSs), all efficiently hydrolyze Nva-tRNAs even when editing of Nva seems redundant. Thus, we hypothesize that editing of Nva-tRNAs had already existed in the last common ancestor of I/L/VRSs, and that the editing domain of I/L/VRSs had primarily evolved to prevent infiltration of Nva into modern proteins.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Escherichia Coli

SUBMITTER: Nicolas Nalpas

LAB HEAD: Boris Macek

PROVIDER: PXD011051 | Pride | 2019-01-28

REPOSITORIES: Pride

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Publications

On the Mechanism and Origin of Isoleucyl-tRNA Synthetase Editing against Norvaline.

Bilus Mirna M Semanjski Maja M Mocibob Marko M Zivkovic Igor I Cvetesic Nevena N Tawfik Dan S DS Toth-Petroczy Agnes A Macek Boris B Gruic-Sovulj Ita I

Journal of molecular biology 20190131 6

Aminoacyl-tRNA synthetases (aaRSs), the enzymes responsible for coupling tRNAs to their cognate amino acids, minimize translational errors by intrinsic hydrolytic editing. Here, we compared norvaline (Nva), a linear amino acid not coded for protein synthesis, to the proteinogenic, branched valine (Val) in their propensity to mistranslate isoleucine (Ile) in proteins. We show that in the synthetic site of isoleucyl-tRNA synthetase (IleRS), Nva and Val are activated and transferred to tRNA at simi ...[more]

PMID: 30711543

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Project description:Propionate is a common three-carbon intermediate produced from the breakdown of propiogenic substrates, such as branched-chain amino acids and odd-numbered fatty acids, and by gut bacteria. Propionate can chemically modify proteins, and if this involves histones, it may underpin a disease-relevant link between short-chain acyls and gene expression in the heart. Here, we sought to characterize how propionate-dependent modifications to histones affect cardiac gene expression and contractile function in a mouse model producing elevated levels of propionate/propionyl-CoA. An adult mouse model of propionic acidaemia (PA) was used to investigate how propionate affects histones and gene expression in the heart, an organ strongly affected in PA patients. Mass spectrometry confirmed elevated plasma propionate in 8-week PA mice, reaching levels detected in PA patient serum. Metabolomic analyses confirmed a metabolic signature of PA, but male mice had enhanced propionate processing towards -alanine. Female PA hearts had expanded end-diastolic and end-systolic volumes, and weaker systolic contractions, without major electrocardiographic changes. Ca2+ signals were deranged in female PA mice (raised diastolic Ca2+), consistent with contractile dysfunction. Differentially-expressed genes (DEGs) included Pde9a and Mme, previously linked to cardiac dysfunction. These DEGs also responded to 48-h culture of wild-type myocytes with propionate as well as butyrate, an HDAC inhibitor, suggesting a role for increased histone acetylation alongside propionylation in inducing these genes. Indeed, histone acetylation (H3K27ac) and propionylation were elevated genome-wide in the PA heart and at the promoters of Pde9a and Mme. These propionate-associated epigenetic responses were more pronounced in female PA mice. The greater prominence of epigenetic, transcriptional, and functional responses in female PA mice, despite a mostly sex-indiscriminate overall metabolic milieu, argues that histone acylation plays a defining role in the cardiac phenotype. We conclude that perturbed propionate metabolism in vivo alters histone acylation and gene expression, which impacts cardiac contractile function.

Dataset Information

On the mechanism and origin of isoleucyl-tRNA synthetase editing against norvaline

Publications

On the Mechanism and Origin of Isoleucyl-tRNA Synthetase Editing against Norvaline.

Similar Datasets

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