  The one-parameter nonrelativistic supersymmetry of Mielnik [J. Math. Phys.
25, 3387 (1984)] is applied to the simple supersymmetric model of Caticha
[Phys. Rev. A 51, 4264 (1995)] in the form used by Rosu [Phys. Rev. E 55, 2038
(1997)] for microtubules. By this means, we introduce Montroll double-well
potentials with singularities that move along the positive or negative
traveling direction depending on the sign of the free parameter of Mielnik's
method. Possible interpretations of the singularity are either microtubule
associated proteins (motors) or structural discontinuities in the arrangement
of the tubulin molecules
