Role of Wybutosine and Mg Ions in Modulating the Structure and Function of tRNA: A Molecular Dynamics Study.

Transfer RNA remains to be a mysterious molecule of the cell repertoire. With its modified bases and selectivity of codon recognition, it remains to be flexible inside the ribosomal machinery for smooth and hassle-free protein biosynthesis. Structural changes occurring in tRNA due to the presence or absence of wybutosine, with and without Mg ions, have remained a point of interest for structural biologists. Very few studies have come to a conclusion correlating the changes either with the structure and flexibility or with the codon recognition. Considering the above facts, we have implemented molecular modeling methods to address these problems using multiple molecular dynamics (MD) simulations of tRNA along with codons. Our results highlight some of the earlier findings and also shed light on some novel structural and functional aspects. Changes in the stability of tRNA in native or codon-bound states result from the conformations of constituent nucleotides with respect to each other. A smaller change in their conformations leads to structural distortions in the base-pairing geometry and eventually in the ribose-phosphate backbone. MD simulation studies highlight the preference of UUC codons over UUU by tRNA in the presence of wybutosine and Mg ions. This study also suggests that magnesium ions are required by tRNA for proper recognition of UUC/UUU codons during ribosomal interactions with tRNA.