Dynamics of apomyoglobin in the alpha-to-beta transition and of partially unfolded aggregated protein.
Changes of molecular dynamics in the alpha-to-beta transition associated with amyloid fibril formation were explored on apomyoglobin (ApoMb) as a model system. Circular dichroism, neutron and X-ray scattering experiments were performed as a function of temperature on the protein, at different solvent conditions. A significant change in molecular dynamics was observed at the alpha-to-beta transition at about 55 degrees C, indicating a more resilient high temperature beta structure phase. A similar effect at approximately the same temperature was observed in holo-myoglobin, associated with partial unfolding and protein aggregation. A study in a wide temperature range between 20 and 360 K revealed that a dynamical transition at about 200 K for motions in the 50 ps time scale exists also for a hydrated powder of heat-denatured aggregated ApoMb.
Institut Laue-Langevin, BP156, Grenoble, France.
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E
Fabiani
A M
AM
Stadler
D
D
Madern
M M
MM
Koza
M
M
Tehei
M
M
Hirai
G
G
Zaccai
D000686:Amyloidosis / Q000503:physiopathology; D001059:Apoproteins / Q000737:chemistry*; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D009211:Myoglobin / Q000737:chemistry*; D033363:Neutron Diffraction; D019999:Pharmaceutical Solutions; D017510:Protein Folding; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D013696:Temperature; D013816:Thermodynamics
D001059:Apoproteins; D009211:Myoglobin; D019999:Pharmaceutical Solutions; C010857:apomyoglobin