Studies of phononlike low-energy excitations of protein molecules by inelastic x-ray scattering.
Molecular dynamics simulations and neutron scattering experiments have shown that many hydrated globular proteins exhibit a universal dynamic transition at TD = 220 K, below which the biological activity of a protein sharply diminishes. We studied the phononlike low-energy excitations of two structurally very different proteins, lysozyme and bovine serum albumin, using inelastic x-ray scattering above and below TD. We found that the excitation energies of the high-Q phonons show a marked softening above TD. This suggests that the large amplitude motions of wavelengths corresponding to this specific Q range are intimately correlated with the increase of biological activities of the proteins.
Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Dazhi
D
Liu
Xiang-qiang
XQ
Chu
Marco
M
Lagi
Yang
Y
Zhang
Emiliano
E
Fratini
Piero
P
Baglioni
Ahmet
A
Alatas
Ayman
A
Said
Ercan
E
Alp
Sow-Hsin
SH
Chen
D004548:Elasticity; D008956:Models, Chemical; D008958:Models, Molecular; D009113:Muramidase / Q000737:chemistry*; D033363:Neutron Diffraction; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013816:Thermodynamics; D014961:X-Ray Diffraction
D012710:Serum Albumin, Bovine; D009113:Muramidase