  We perform molecular dynamics simulations for a simple coarse-grained model
of crambin placed inside of a softly repulsive sphere of radius R. The
confinement makes folding at the optimal temperature slower and affects the
folding scenarios, but both effects are not dramatic. The influence of crowding
on folding are studied by placing several identical proteins within the sphere,
denaturing them, and then by monitoring refolding. If the interactions between
the proteins are dominated by the excluded volume effects, the net folding
times are essentially like for a single protein. An introduction of
inter-proteinic attractive contacts hinders folding when the strength of the
attraction exceeds about a half of the value of the strength of the single
protein contacts. The bigger the strength of the attraction, the more likely is
the occurrence of aggregation and misfolding.
