Conformations and dynamics of adsorbed protein-like chains

Conformations and dynamics of adsorbed protein-like chains are investigated by using Monte Carlo simulation based on the modified orientation-dependent monomer-monomer interaction (ODI) model. The chain size and shape of adsorbed protein-like chains, such as mean-square end-to-end distance < R-2 >, mean-square radius of gyration < S-2 >(xy) or < S-2 >(z)), shape factors (sf(i)*) (i = 1, 2, 3), and <delta*> are discussed here. At the same time, fraction of adsorbed segment f(a) and average orientation of bond < P-2(Cos theta)> are also investigated. The adsorbed protein-like chains trend to be more flat when adsorption interaction energy becomes strong. Different kinds of interactions (such as contact interaction, sheet interaction, spin-spin interaction, helical interaction, and adsorbed interaction) are considered in detail. Dynamics of adsorbed protein-like chains are investigated by calculating their diffusion coefficients, and we find that there exist the relationships of D-xy similar to N-xy(-gamma) and D-z similar to N-z(-gamma), and the values of gamma(xy) and gamma(z) are 4-5 times larger than that of general self-avoiding walk (SAW) chains. These investigations may provide some insights into adsorption of proteins. (c) 2005 Elsevier Ltd. All rights reserved.