4nbj
From Proteopedia
D-aminoacyl-tRNA deacylase (DTD) from Plasmodium falciparum in complex with D-tyrosyl-3'-aminoadenosine at 2.20 Angstrom resolution
Structural highlights
FunctionDTD_PLAF7 D-aminoacyl-tRNA deacylase, with no observable activity on tRNAs charged with their cognate L-amino acid (PubMed:20007323, PubMed:24302572, PubMed:27224426). Probably acts by rejecting L-amino acids from its binding site rather than specific recognition of D-amino acids (PubMed:27224426). Catalyzes the hydrolysis of D-tyrosyl-tRNA(Tyr), has no activity on correctly charged L-tyrosyl-tRNA(Tyr) (PubMed:20007323, PubMed:24302572, PubMed:27224426). Hydrolyzes correctly charged, achiral, glycyl-tRNA(Gly) (PubMed:27224426). Deacylates mischarged D.melanogaster and E.coli glycyl-tRNA(Ala) (PubMed:28362257). Probably acts via tRNA-based rather than protein-based catalysis (PubMed:24302572, PubMed:27224426). Acts on tRNAs only when the D-amino acid is either attached to the ribose 3'-OH or transferred to the 3'-OH from the 2'-OH through rapid transesterification (PubMed:24302572). Binds a number of other D-amino acids (D-Arg, D-Glu, D-His, D-Lys, D-Ser), suggesting it may also deacylate other mischarged tRNAs (PubMed:20007323).[1] [2] [3] [4] Publication Abstract from PubMedThe biological macromolecular world is homochiral and effective enforcement and perpetuation of this homochirality is essential for cell survival. In this study, we present the mechanistic basis of a configuration-specific enzyme that selectively removes D-amino acids erroneously coupled to tRNAs. The crystal structure of dimeric D-aminoacyl-tRNA deacylase (DTD) from Plasmodium falciparum in complex with a substrate-mimicking analog shows how it uses an invariant 'cross-subunit' Gly-cisPro dipeptide to capture the chiral centre of incoming D-aminoacyl-tRNA. While no protein residues are directly involved in catalysis, the unique side chain-independent mode of substrate recognition provides a clear explanation for DTD's ability to act on multiple D-amino acids. The strict chiral specificity elegantly explains how the enriched cellular pool of L-aminoacyl-tRNAs escapes this proofreading step. The study thus provides insights into a fundamental enantioselection process and elucidates a chiral enforcement mechanism with a crucial role in preventing D-amino acid infiltration during the evolution of translational apparatus. DOI: http://dx.doi.org/10.7554/eLife.01519.001. Mechanism of chiral proofreading during translation of the genetic code.,Ahmad S, Routh SB, Kamarthapu V, Chalissery J, Muthukumar S, Hussain T, Kruparani SP, Deshmukh MV, Sankaranarayanan R Elife. 2013 Dec 3;2(0):e01519. doi: 10.7554/eLife.01519. PMID:24302572[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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