PUBLICATION
Role of D-aminoacyl-tRNA deacylase beyond chiral proofreading as a cellular defense against glycine mischarging by AlaRS
- Authors
- Pawar, K.I., Suma, K., Seenivasan, A., Kuncha, S.K., Routh, S.B., Kruparani, S.P., Sankaranarayanan, R.
- ID
- ZDB-PUB-200522-30
- Date
- 2017
- Source
- eLIFE 6: (Journal)
- Registered Authors
- Keywords
- E. coli, amino acids, biochemistry, biophysics, chirality, genetic code, structural biology, tRNA synthetase, translation
- MeSH Terms
-
- Alanine-tRNA Ligase/antagonists & inhibitors*
- Aminoacyltransferases/metabolism*
- Escherichia coli/enzymology*
- Escherichia coli/metabolism*
- Glycine/metabolism*
- PubMed
- 28362257 Full text @ Elife
Citation
Pawar, K.I., Suma, K., Seenivasan, A., Kuncha, S.K., Routh, S.B., Kruparani, S.P., Sankaranarayanan, R. (2017) Role of D-aminoacyl-tRNA deacylase beyond chiral proofreading as a cellular defense against glycine mischarging by AlaRS. eLIFE. 6:.
Abstract
Strict L-chiral rejection through Gly-cisPro motif during chiral proofreading underlies the inability of D-aminoacyl-tRNA deacylase (DTD) to discriminate between D-amino acids and achiral glycine. The consequent Gly-tRNAGly 'misediting paradox' is resolved by EF-Tu in the cell. Here, we show that DTD's active site architecture can efficiently edit mischarged Gly-tRNAAla species four orders of magnitude more efficiently than even AlaRS, the only ubiquitous cellular checkpoint known for clearing the error. Also, DTD knockout in AlaRS editing-defective background causes pronounced toxicity in Escherichia coli even at low-glycine levels which is alleviated by alanine supplementation. We further demonstrate that DTD positively selects the universally invariant tRNAAla-specific G3•U70. Moreover, DTD's activity on non-cognate Gly-tRNAAla is conserved across all bacteria and eukaryotes, suggesting DTD's key cellular role as a glycine deacylator. Our study thus reveals a hitherto unknown function of DTD in cracking the universal mechanistic dilemma encountered by AlaRS, and its physiological importance.
Genes / Markers
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Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
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Engineered Foreign Genes
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