  For molecules weakly coupled to leads the exact linear Kohn-Sham (KS)
conductance can be orders of magnitude larger than the true linear conductance
due to the lack of dynamical exchange-correlation (xc) corrections. In this
work we show how to incorporate dynamical effects in KS transport calculations.
The only quantity needed is the static xc potential in the molecular junction.
Our scheme provides a comprehensive description of Coulomb blockade without
breaking the spin symmetry. This is explicitly demonstrated in single-wall
nanotubes where the corrected conductance is in good agreement with
experimental data whereas the KS conductance fails dramatically.
