Аннотация
Boundary element methods are used to model the free solution electrophoretic
mobility of short DNA fragments. The Stent surfaces of the DNA fragments
are modeled as plated cylinders that reproduce translational and
rotational diffusion constants. The solvent-accessible and ion-accessible
surfaces are taken to be coincident with the Stern surface. The mobilities
are computed by solving simultaneously the coupled Navier-Stokes,
Poisson, and ion-transport equations. The equilibrium electrostatics
are treated at the level of the full Poisson-Boltzmann equation and
ion relaxation is included. For polyions as highly charged as short
DNA fragments, ion relaxation is substantial. At .11 M KCl, the simulated
mobilities of a 20 base pair DNA fragment are in excellent agreement
with experiment. At .04 M Tris acetate, pH = 8.0, the simulated mobilities
are about 10-15% higher than experimental values and this discrepancy
is attributed to the relatively large size of the Tris counterion.
The length dependence of the mobility at .11 M KCl is also investigated.
Earlier mobility studies an lysozyme are reexamined in view of the
presentfindings. In addition to electrophoretic mobilities, the effective
polyion charge measured in steady state electrophoresis and its relationship
to the preferential interaction parameter Gamma is briefly considered.
(C) 1998 John Wiley & Sons, Inc.
Пользователи данного ресурса
Пожалуйста,
войдите в систему, чтобы принять участие в дискуссии (добавить собственные рецензию, или комментарий)