Similarity of force-induced unfolding of apomyoglobin to its chemical-induced unfolding: an atomistic molecular dynamics simulation approach.
We have compared force-induced unfolding with traditional unfolding methods using apomyoglobin as a model protein. Using molecular dynamics simulation, we have investigated the structural stability as a function of the degree of mechanical perturbation. Both anisotropic perturbation by stretching two terminal atoms and isotropic perturbation by increasing the radius of gyration of the protein show the same key event of force-induced unfolding. Our primary results show that the native structure of apomyoglobin becomes destabilized against the mechanical perturbation as soon as the interhelical packing between the G and H helices is broken, suggesting that our simulation results share a common feature with the experimental observation that the interhelical contact is more important for the folding of apomyoglobin than the stability of individual helices. This finding is further confirmed by simulating both helix destabilizing and interhelical packing destabilizing mutants.
Choi
Ho Sup
HS
Hyperstructured Organic Materials Research Center, School of Material Science and Engineering, Seoul National University, Seoul 151-742, Korea.
Huh
June
J
Jo
Won Ho
WH
D000818:Animals; D001059:Apoproteins / Q000737:chemistry* / Q000235:genetics; D055592:Biophysical Phenomena; D001703:Biophysics; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015233:Models, Statistical; D009068:Movement; D009154:Mutation; D009211:Myoglobin / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013997:Time Factors; D014907:Whales
D001059:Apoproteins; D009211:Myoglobin; C010857:apomyoglobin