Evolutionary stabilization of generous replicases by complex formation

The importance of spatial organization for the evolutionary stability of trans-acting replicase systems ($T\buildrel X \over \longrightarrow 2T)$, where T is a general member of a combinatorial family including the special catalyst X, is now well established, by analytical and Monte Carlo models [1,2]. Complex formation as an intermediate step in replication ($X+T\rightleftharpoons XT\to X+2T)$, besides refining the model, enhances co-localization of replicase X and templates T and is shown here to thereby contribute to the evolutionary stability of the catalyst. Applying the established individual molecule stochastic PRESS-framework [3], the performances of cooperative replication with and without intermediate complex formation are compared, and the beneficial effect of complex formation as enhancing stability is studied numerically under various conditions. The results obtained are of value for studies of prebiotic evolution, but also point towards a possible mechanism for stabilizing replication systems in adaptive molecular engineering