Monte Carlo simulation study of melittin: Protein folding and temperature dependence

The tetramerization of melittin, a 26-amino-acid peptide, is considered as a model for protein folding. The Monte Carlo simulation was used to study the folding arrangement of melittin, and the results are compared with the experiment. An acceptance rate of 50% for new configurations is achieved by using ranges of ±0.001 Å for the translations and ±15°C for the rotations. Around 311 K, the folded structure of the protein has the greatest stability; the range from −40 to −80 shows the best ϕ angles for melittin. The final optimized structure of melittin strongly depends on the temperature. The melittin tetramer is found to have a temperature of maximum stability ranging from 35.5 to 43°C.