Investigation of Phe-tRNA interaction with EF-Tu in GDP/GTP nucleotide bound states: a molecular dynamics simulation study

Abstract

Elongation factor Tu (EF-Tu) is an important class of translational GTPases (trGTPases) involved in the elongation process. EF-Tu functions by forming the tight complex with the aminoacyl-tRNA (aa-tRNA: transfer RNA carrying an amino acid) in the GTP-bound active state and subsequently transports the aa-tRNA to the A-site (aminoacyl-site) of the ribosome. The correct interaction between mRNA's codon and aa-tRNA anticodon triggers GTP hydrolysis, resulting in the transition of EF-Tu from the active state to the inactive state (EF-Tu bound to GDP). This, in turn, results in the dissociation of EF-Tu:GDP from the tRNA and ribosome. However, the conformational changes and interactions responsible for the tight complex formation between EF-Tu and aa-tRNA in the GTP-bound state and the disruption of the interaction between EF-Tu and aa-tRNA in the GDP-bound state are not well understood. Therefore, to explore the conformational changes in the EF-Tu:Phe-tRNA complex and to get insight into the interaction between Phe-tRNA (tRNA carrying Phenylalanine) and EF-Tu in GDP/GTP nucleotide bound state, 200 ns MD (molecular dynamics) simulation have been carried out. The RMSD, RMSF, cluster, and DSSP analyses suggest that the GTP-bound state attains a more favorable conformation, which may facilitate EF-Tu’s interactions with the tRNA and ribosome. Further investigation of the non-bonded interaction energy calculation revealed the significance of domainII in interaction with the Phe-tRNA in a GTP-bound state. In addition, the H-bonds calculated between the tRNA’s Phe (Phenylalanine attached to the tRNA is considered) and domainII highlights the contribution of Val285 in recognizing tRNA’s Phe by forming an H-bond throughout the simulation time in the GTP bound state. Overall these results provide insight into how GTP nucleotide influences the interaction between EF-Tu and Phe-tRNA.