  Macromolecular protein complexes catalyze essential physiological processes
that sustain life. Various interactions between protein subunits could increase
the effective mass of certain peptide groups, thereby compartmentalizing
protein $\alpha$-helices. Here, we study the differential effects of applied
massive barriers upon the soliton-assisted energy transport within proteins. We
demonstrate that excentric barriers, localized onto a single spine in the
protein $\alpha$-helix, reflect or trap three-spine solitons as effectively as
concentric barriers with comparable total mass. Furthermore, wider protein
solitons, whose energy is lower, require heavier massive barriers for soliton
reflection or trapping. Regulation of energy transport, delivery and
utilization at protein active sites could thus be achieved through control of
the soliton width, or of the effective mass of the protein subunits.
