Question

Explain how mRNAs translocate on the ribosome.

Answer 1

Translocation is a fundamental step in the elongation cycle of protein synthesis in which mRNA that is combined with tRNAs by codon-anticodon association is traveled through the ribosome. It has been very much reported that the kinetics of mRNA translocation for the most part indicates biphasic character. In any case, the physical premise of the marvel is misty. Here, to clarify the marvel we consider two models. In one (Model I), other than the traditional non-turned and pivoted adaptations of the ribosome there additionally exists a halfway compliance between the two established conformities. The mRNA translocation happens through continuing from the pivoted (hybrid) pretranslocation to halfway to non-turned posttranslocation state. In another (Model II), just the established non-pivoted and turned adaptations are considered. Before EF-G official, the ribosomal complex is in either the traditional non-pivoted or turned (hybrid) pretranslocation state, with the equilibrium with each other. EF-G can tie to the two states and afterward the mRNA translocation happens by means of continuing either specifically from the hybrid to non-pivoted posttranslocation state or from the non-turned pretranslocation to hybrid to non-turned posttranslocation state. Systematic examinations demonstrated that Model I can't clarify the biphasic character of mRNA translocation. By differentiate, Model II can not just give a decent clarification of the biphasic character of mRNA translocation yet in addition clarify the kinetics of the invert ribosomal turn from the pivoted to non-pivoted adaptation, which can be fit to a solitary exponential. In this manner, Model II could be the fitting one for the kinetic pathway of mRNA translocation.