ELASTIC BEHAVIOR OF PROTEIN-LIKE SINGLE CHAIN

The conformational properties and elastic behaviors of protein-like single chains in the process of tensileelongation were investigated by means of Monte Carlo method.The sequences of protein-like single chains contain two typesof residues:hydrophobic（H）and hydrophilic（P）.The average conformations and thermodynamics statistical properties ofprotein-like single chains with various elongation ratio λwere calculated.It was found that the mean-square end-to-enddistance<R;>（?）.increases with elongation ratio λ.The tensor eigenvalues ratio of<L;>:<L;>decreases with elongationratio λfor short（HP）;protein-like polymers,however,the ratio of<L;>:<L;>increases with elongation ratio λ,especially for long （H）;sequence.Average energy per bond <U> increases with elongation ratio λ,especially for （H）;protein-like single chains.Helmholtz free energy per bond also increases with elongation ratio λ.Elastic force（f）,energycontribution to force（f;）and entropy contribution to force（fs）for different protein-like single chains were also calculated.These investigations may provide some insights into elastic behaviors of proteins.