Methylation at position 32 of tRNA catalyzed by TrmJ alters oxidative stress response in Pseudomonas aeruginosa

• Published in: Nucleic acids research 2016-12, Vol.44 (22), p.10834-10848
• Main Authors: Jaroensuk, Juthamas, Atichartpongkul, Sopapan, Chionh, Yok Hian, Wong, Yee Hwa, Liew, Chong Wai, McBee, Megan E, Thongdee, Narumon, Prestwich, Erin G, DeMott, Michael S, Mongkolsuk, Skorn, Dedon, Peter C, Lescar, Julien, Fuangthong, Mayuree
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacterial Proteins - chemistry; Bacterial Proteins - physiology; Base Sequence; Catalytic Domain; Crystallography, X-Ray; Hydrogen Peroxide - pharmacology; Life Sciences; Methylation; Models, Molecular; Nucleic Acid Enzymes; Oxidative Stress; Pseudomonas aeruginosa - drug effects; Pseudomonas aeruginosa - enzymology; RNA, Bacterial - chemistry; RNA, Transfer - metabolism; tRNA Methyltransferases - chemistry; tRNA Methyltransferases - physiology
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gkw870

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 and tRNA are substrates for Cm formation, tRNA , tRNA , tRNA and tRNA for Um, and tRNA for Am. tRNA , 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 and Um in tRNA 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 H O 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.