Structure and two-metal mechanism of fungal tRNA ligase Journal Article

   


Authors: Banerjee, A.; Ghosh, S.; Goldgur, Y.; Shuman, S.
Article Title: Structure and two-metal mechanism of fungal tRNA ligase
Abstract: Fungal tRNA ligase (Trl1) is an essential enzyme that repairs RNA breaks with 2,3-cyclic-PO4 and 5-OH ends inflicted during tRNA splicing and non-canonical mRNA splicing in the fungal unfolded protein response. Trl1 is composed of C-terminal cyclic phosphodiesterase (CPD) and central GTP-dependent polynucleotide kinase (KIN) domains that heal the broken ends to generate the 3-OH,2-PO4 and 5-PO4 termini required for sealing by an N-terminal ATP-dependent ligase domain (LIG). Here we report crystal structures of the Trl1-LIG domain from Chaetomium thermophilum at two discrete steps along the reaction pathway: the covalent LIG-(lysyl-N)-AMP center dot Mn2+ intermediate and a LIG center dot ATP center dot(Mn2+)(2) Michaelis complex. The structures highlight a two-metal mechanism whereby a penta-hydrated metal complex stabilizes the transition state of the ATP phosphate and a second metal bridges the and phosphates to help orient the pyrophosphate leaving group. A LIG-bound sulfate anion is a plausible mimetic of the essential RNA terminal 2-PO4. Trl1-LIG has a distinctive C-terminal domain that instates fungal Trl1 as the founder of an Rnl6 clade of ATP-dependent RNA ligase. We discuss how the Trl1-LIG structure rationalizes the large body of in vivo structure-function data for Saccharomyces cerevisiae Trl1.
Keywords: mutational analysis; phosphate; repair; polypeptide; domain; specificity; polynucleotide kinase; plant; rtcb; reveal
Journal Title: Nucleic Acids Research
Volume: 47
Issue: 3
ISSN: 0305-1048
Publisher: Oxford University Press  
Date Published: 2019-02-20
Start Page: 1428
End Page: 1439
Language: English
ACCESSION: WOS:000467960500034
DOI: 10.1093/nar/gky1275
PROVIDER: wos
PMCID: PMC6379707
PUBMED: 30590734
Notes: Article -- Source: Wos
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MSK Authors
  1. Stewart H Shuman
    548 Shuman
  2. Yehuda Goldgur
    42 Goldgur
  3. Shreya Ghosh
    12 Ghosh
  4. Ankan Banerjee
    9 Banerjee
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