  We have performed a multicanonical molecular dynamics simulation on a simple
model protein.We have studied a model protein composed of charged, hydrophobic,
and neutral spherical bead monomers.Since the hydrophobic interaction is
considered to significantly affect protein folding, we particularly focus on
the competition between effects of the Coulomb interaction and the hydrophobic
interaction. We found that the transition which occurs upon decreasing the
temperature is markedly affected by the change in both parameters and forms of
the hydrophobic potential function, and the transition changes from first order
to second order, when the Coulomb interaction becomes weaker.
