  We study the role of topological restrictions for the conformational
structure of a nonphantom homopolymer chain in a lattice Monte Carlo model. In
the athermal regime we find that the standard Metropolis algorithm violates the
detailed balance condition if both local monomer and global reptational moves
are included. However, if about 1 reptation is performed per N local moves the
balance is recovered and we obtain the Flory exponent value close to nu=0.588,
where N is the degree of polymerisation. We also find that the structure of the
collapsed globule is different at equilibrium from that after the late stage of
folding kinetics. Namely, due to reptations the end, and even more so, the
penultimate monomer groups tend to be buried inside the globule core with other
monomers thus being more exposed to the surface.
