Methylation at position 32 of tRNA catalyzed by TrmJ alters oxidative stress response in Pseudomonas aeruginosa
Author(s)Jaroensuk, Juthamas; Atichartpongkul, Sopapan; Wong, Yee Hwa; Liew, Chong Wai; McBee, Megan E.; Thongdee, Narumon; Prestwich, Erin G.; Mongkolsuk, Skorn; Lescar, Julien; Fuangthong, Mayuree; Chionh, Yok Hian; DeMott, Michael S; Dedon, Peter C; ... Show more Show less
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Bacteria respond to environmental stresses using a variety of signaling and gene expression pathways, with translational mechanisms being the least well understood. Here, we identified a tRNA methyltransferase in Pseudomonas aeruginosa PA14, trmJ, which confers resistance to oxidative stress. Analysis of tRNA from a trmJ mutant revealed that TrmJ catalyzes formation of Cm, Um, and, unexpectedly, Am. Defined in vitro analyses revealed that tRNA[superscript Met(CAU)] and tRNA[superscript Trp(CCA)] are substrates for Cm formation, tRNA[superscript Gln(UUG)], tRNA[superscript Pro(UGG)], tRNA[superscript Pro(CGG)] and tRNA[superscript His(GUG)] for Um, and tRNA[superscript Pro(GGG)] for Am. tRNA[superscript Ser(UGA)], previously observed as a TrmJ substrate in Escherichia coli, was not modified by PA14 TrmJ. Position 32 was confirmed as the TrmJ target for Am in tRNA[superscriptPro(GGG)] and Um in tRNA[superscript Gln(UUG)] by mass spectrometric analysis. Crystal structures of the free catalytic N-terminal domain of TrmJ show a 2-fold symmetrical dimer with an active site located at the interface between the monomers and a flexible basic loop positioned to bind tRNA, with conformational changes upon binding of the SAM-analog sinefungin. The loss of TrmJ rendered PA14 sensitive to H2O2 exposure, with reduced expression of oxyR-recG, katB-ankB, and katE. These results reveal that TrmJ is a tRNA:Cm32/Um32/Am32 methyltransferase involved in translational fidelity and the oxidative stress response.
DepartmentMassachusetts Institute of Technology. Department of Biological Engineering
Nucleic Acids Research
Oxford University Press
Jaroensuk, Juthamas, et al. “ Methylation at Position 32 of tRNA Catalyzed by TrmJ Alters Oxidative Stress Response in Pseudomonas Aeruginosa.” Nucleic Acids Research 44, no. 22 (September 28, 2016): 10834–10848.
Final published version