FOLDING RATE AND STABILITY OF NATIVE STRUCTURE IN RANDOM AND EDITED CHAINS

The kinetics of reaching a ''native'' state in a simplest model hetero polymer allowing link pairing was modeled numerically by the Monte Car lo method in a broad range of temperatures and solvent quality. There proved to be ''optimal'' conditions where the native structure is reac hed rapidly, without exhausting all chain conformations. This process is fast even for a random sequence; however, the resulting spatial str ucture is thermodynamically unstable in this temperature and solvent q uality range optimal for folding. At the same time, sequences speciall y edited to reinforce the native structure are stable in the kinetical ly optimal range, and thus only such chains rapidly reach a thermodyna mically stable native state.