Mathematical aspects of the ultraviolet photochemistry of poly U

Abstract

Two mathematical models have been formulated to predict the yield of dimer and hydrate photoproducts in poly U. These two methods, the Monte Carlo method and the random distribution method, require the use of a digital computer for solution. They have been found to give identical results except at large exposures. At large exposures the random distribution method is less accurate than the Monte Carlo method; but nevertheless the random distribution method is preferred for practical calculations because of its simplicity and because it requires shorter computing times. In addition, it is easily modified for more complicated reaction schemes. These theoretical models are useful in that they allow the calculation of the relative frequency of any sequence of photoproducts within the population of irradiated poly U molecules. Such calculations of product sequences may be helpful in evaluating the role of dimer and hydrate photoproducts in the ultraviolet inactivation of poly U used as a messenger RNA or as a template RNA.