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Mg2+-Dependent Methyl Transfer By A Knotted Protein: A Molecular Dynamics Simulation And Quantum Mechanics Study, Agata P Perlinska, Marcin Kalek, Thomas Christian, Ya-Ming Hou, Joanna I Sulkowska

Department of Biochemistry and Molecular Biology Faculty Papers

Mg2+ is required for the catalytic activity of TrmD, a bacteria-specific methyltransferase that is made up of a protein topological knot-fold, to synthesize methylated m1G37-tRNA to support life. However, neither the location of Mg2+ in the structure of TrmD nor its role in the catalytic mechanism is known. Using molecular dynamics (MD) simulations, we identify a plausible Mg2+ binding pocket within the active site of the enzyme, wherein the ion is coordinated by two aspartates and a glutamate. In this position, Mg2+ additionally interacts with the carboxylate of a methyl donor cofactor S-adenosylmethionine (SAM). The computational results are validated by …