{"doi":"10.1101/2020.09.11.293571","title":"Human <i>trans</i> -editing enzyme displays tRNA acceptor stem specificity and relaxed amino acid selectivity","abstract":"Abstract Accurate translation of genetic information into proteins is vital for cell sustainability. ProXp-ala prevents proteome-wide Pro-to-Ala mutations by hydrolyzing misacylated Ala-tRNA Pro , which is synthesized by prolyl-tRNA synthetase (ProRS). Bacterial ProXp-ala was previously shown to combine a size-based exclusion mechanism with conformational and chemical selection for the recognition of the alanyl moiety, while tRNA Pro is selected via recognition of tRNA acceptor stem elements G72 and A73. The identity of these critical bases changed during evolution with eukaryotic cytosolic tRNA Pro possessing a cytosine at the corresponding positions. The mechanism by which eukaryotic ProXp-ala adapted to these changes remains unknown. In this work, recognition of the aminoacyl moiety and tRNA acceptor stem by human ( Hs ) ProXp-ala was examined. Enzymatic assays revealed that Hs ProXp-ala requires C72 and C73 in the context of Hs cytosolic tRNA Pro for efficient deacylation of mischarged Ala-tRNA Pro . The strong dependence on these bases prevents cross-species deacylation of bacterial Ala-tRNA Pro or of Hs mitochondrial Ala-tRNA Pro by the human enzyme. Similar to the bacterial enzyme, Hs ProXp-ala showed strong tRNA acceptor-stem recognition but differed in its amino acid specificity profile relative to bacterial ProXp-ala. Changes at conserved residues in both the Hs and bacterial ProXp-ala substrate binding pockets modulated this specificity. These results illustrate how the mechanism of substrate selection diverged during the evolution of the ProXp-ala family and provides the first example of a trans -editing domain whose specificity evolved to adapt to changes in its tRNA substrate.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2020,"id":130999,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9543,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":481345,"name":"Marina Bakhtina","orcid":"0000-0003-0322-1901","position":1,"is_corresponding":false},{"id":584951,"name":"Daniel McGowan","orcid":null,"position":2,"is_corresponding":false},{"id":584952,"name":"Jawad Abid","orcid":null,"position":3,"is_corresponding":false},{"id":426659,"name":"Yuki Goto","orcid":"0000-0003-4317-0790","position":4,"is_corresponding":false},{"id":426660,"name":"Hiroaki Suga","orcid":"0000-0002-5298-9186","position":5,"is_corresponding":false},{"id":377519,"name":"Karin Musier‐Forsyth","orcid":null,"position":6,"is_corresponding":false},{"id":584295,"name":"Oscar Vargas‐Rodriguez","orcid":"0000-0002-2301-2800","position":0,"is_corresponding":true}],"reference_count":50,"raw_metadata":null,"created_at":"2026-07-18T23:16:00.235845Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}