A Model for Proto-tRNA Loading

A kinetic model for loading of proto-tRNA is presented. The kinetic parameters were first estimated from the results of Francklyn & Schimmel (1989;Nature337, 478–481), who studied the aminoacylation of both tRNA and its minihelix. Then these parameters were reduced several-fold, as is more appropriate for the prebiotic world. The simulations revealed a very slow time course of the loading reaction. We also consider a possibility for the proto-tRNA loading without a catalyst and discuss the feasibility of such processes. Analytical approximations are presented for the kinetics of proto-tRNA loading with and without enzyme. An estimate is given for the time required for the development of template- and sequence-directed systems.