Protein-like copolymers: computer simulation

The model of AB copolymers with a "protein-like" primary sequence was developed. This type of copolymers was obtained in a computer experiment. First, the conformation of a collapsed dense homopolymer globule was generated and then, based on this conformation, the primary AB sequence was determined by denoting the monomeric units located near the surface of the globule as units A and those constituting the core of the globule as units B. After that, the primary structure of the chain was fixed, and different interaction potentials for the A and B units were introduced. Drawing an analogy of this model to aqueous solutions of globular proteins, A units were interpreted as hydrophilic, and B units were regarded as hydrophobic. By means of Monte Carte simulation using the bond fluctuation model, the coil-globule transition in "protein-like" AB copolymer, induced by an increase in the attraction between the hydrophobic tl units, was stud:ed. The coil-globule transition in a copolymer with the "protein-like" primary sequence occurs at a higher temperature and has higher rate and is sharper than that in a random copolymer with the same A/B composition and in a random block copolymer with the same A/B composition and the same "degree of blockiness".