Polymer Chain Folding

HP lattice protein model — hydrophobic collapse by Monte Carlo
H-P-H-H-P-H-H-P-P-H
Energy: 0 | HH contacts: 0
MC steps: 0 | T: 1.0
0.50
1.5
The HP model reduces protein folding to a 2D lattice problem. Each residue is either Hydrophobic (H, orange) or Polar (P, blue). Hydrophobic residues attract each other: each non-bonded H-H neighbor contact contributes −1 to energy. Monte Carlo optimization with pivot moves and simulated annealing guides the chain toward compact, low-energy structures — the "folded" state. This models the hydrophobic collapse driving protein folding.