Role of D-aminoacyl-tRNA deacylase beyond chiral proofreading as a cellular defense against glycine mischarging by AlaRS.

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-tRNA^Gly 'misediting paradox' is resolved by EF-Tu in the cell. Here, we show that DTD's active site architecture can efficiently edit mischarged Gly-tRNA^Ala 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 invarian

SUBMITTER: Pawar KI 

PROVIDER: S-EPMC5409826 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature