Theoretical Estimates of Physical Aspects Involved in the Power Stroke Hypothesis for Ribosome Translocation

Abstract

The power stroke mechanism for ribosome translocation is evaluated through calculations of basic aspects of the mechanics, hydrodynamics, and elasticity involved in such a process. The results show that reported power stroke magnitudes would generate several physical problems for ribosome translocation: unwanted or disproportionate displacements of the ribosome and mRNA, destabilizing competing forces and high tension on the mRNA in the ribosome tunnel. All these issues can be related to the ribosome losing its correct reading frame during mRNA translation. To improve ribosome translocation models, the suggestion is to change the focus from tRNA–mRNA forced displacement to ribosome motion along the mRNA. Also, to consider that the mRNA is essentially different from cytoskeleton fibers and that the ribosome does not work alone during mRNA translation.