Free energy calculations of RNA interactions

This review discusses the use of molecular dynamics free energy calculations for characterizing RNA interactions, with particular emphasis on molecular recognition events involved in mRNA translation on the ribosome. The general methodology for efficient free energy calculations is outlined and our specific implementation for binding free energy changes due to base mutations in mRNA and tRNA is described. We show that there are a number of key problems related to the accuracy of protein synthesis that can be addressed with this type of computational approach and several such examples are discussed in detail. These include the decoding of mRNA during peptide chain elongation, initiation and termination of translation, as well as the energetic effects of base tautomerization and tRNA modifications. It is shown that free energy calculations can be made sufficiently reliable to allow quantitative conclusions to be drawn regarding the energetics of cognate versus non-cognate interactions and its structural origins.