Protein Structure - 4

Accessible and buried surface area

  • Accessible surface area (A.S.A) is obtained by rolling a solvent molecule (ususllay water with radius 1.4Å) over the surface of the protein.

  • Each Å2 of buried surface area contributes 105 J of free energy of stabilization.
  • For monomeric proteins of up to 300 aa residues, A.S.A = 11.1 M2/3.
  • Average A.S.A of monomeric proteins
    • Exterior
    • ~ 58% nonpolar
    • ~ 29% polar
    • ~ 13% charged
    • Interior
    • ~ 60% nonpolar
    • ~ 33% polar
    • ~ 7% charged