Symmetry-broken reactant motion upon phase-related symmetrically modulated excitations: application to highly selective molecular sorting.
ABSTRACT This paper introduces a separation protocol relying on affinity chromatography that exhibits unprecedented selectivities. We submit the mixture contained in the separative medium to the simultaneous action of two symmetrically modulated excitations. The first is a uniform periodic field (e.g., electric field) with zero mean value, whereas the second is the periodic modulation of a thermodynamic parameter such as the temperature. Under appropriate tuning of the modulations with the dynamics of the discriminating chemical reaction, we predict a symmetry breaking of molecular motion: the mixture components that are addressed by their rate constants exhibit an oriented motion for a particular phase relation between the modulations of the field and the thermodynamic parameter. The resulting velocity of the mixture components depends on the rate constants and on a conjugated thermodynamic value such as the standard enthalpy of the discrimination process in the case of a temperature modulation. In particular, it may be possible to separate mixture components with identical rate constants. We use the present approach to design a protocol to sort nucleic acids by their sequence.
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ABSTRACT: We consider n reactive species involved in unimolecular reactions and submitted to a temperature modulation of small amplitude. We determine the conditions on the rate constants for which the deviations from the equilibrium concentrations of each species can be optimized and find the analytical expression of the frequency associated with an extremum of concentration shift in the case n=3. We prove that the frequency dependence of the displacement of equilibrium gives access to the number n of species involved in the mechanism. We apply the results to the case of the transformation of a reactant into a product through a possible reactive intermediate and find the order relation obeyed by the activation energies of the different barriers. The results typically apply to enzymatic catalysis with kinetics of Michaelis-Menten type.Physical Review E 12/2007; 76(5 Pt 2):056112. · 2.31 Impact Factor