Characterization of the tRNA ligases of pathogenic fungi Aspergillus fumigatus and Coccidioides immitis Journal Article


Authors: Remus, B. S.; Schwer, B.; Shuman, S.
Article Title: Characterization of the tRNA ligases of pathogenic fungi Aspergillus fumigatus and Coccidioides immitis
Abstract: Yeast tRNA ligase (Trl1) is an essential trifunctional enzyme that repairs RNA breaks with 2′,3′-cyclic-PO4 and 5′-OH ends. Trl1 is composed of C-terminal cyclic phosphodiesterase and central polynucleotide kinase domains that heal the broken ends to generate the 3′-OH, 2′-PO4, and 5′-PO4 termini required for sealing by an N-terminal ligase domain. Trl1 enzymes are found in all human fungal pathogens and they are promising targets for antifungal drug discovery because: (i) their domain structures and biochemical mechanisms are unique compared to the mammalian RtcB-type tRNA splicing enzyme; and (ii) there are no obvious homologs of the Trl1 ligase domain in mammalian proteomes. Here we characterize the tRNA ligases of two human fungal pathogens: Coccidioides immitis and Aspergillus fumigatus. The biological activity of CimTrl1 and AfuTrl1 was verified by showing that their expression complements a Saccharomyces cerevisiae trl1Δ mutant. Purified recombinant AfuTrl1 and CimTrl1 proteins were catalytically active in joining 2′,3′-cyclic-PO4 and 5′-OH ends in vitro, either as full-length proteins or as a mixture of separately produced healing and sealing domains. The biochemical properties of CimTrl1 and AfuTrl1 are similar to those of budding yeast Trl1, particularly with respect to their preferential use of GTP as the phosphate donor for the polynucleotide kinase reaction. Our findings provide genetic and biochemical tools to screen for inhibitors of tRNA ligases from pathogenic fungi. © 2016 Remus et al.
Keywords: trna splicing; antifungal target
Journal Title: RNA
Volume: 22
Issue: 10
ISSN: 1355-8382
Publisher: Cold Spring Harbor Laboratory Press  
Date Published: 2016-10-01
Start Page: 1500
End Page: 1509
Language: English
DOI: 10.1261/rna.057455.116
PROVIDER: scopus
PMCID: PMC5029449
PUBMED: 27492257
DOI/URL:
Notes: Article -- Export Date: 2 November 2016 -- Source: Scopus
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  1. Stewart H Shuman
    546 Shuman
  2. Barbara Remus
    6 Remus