Spatio - temporal features of protein specific motions. The influence of hydration.
The angular dependencies of inelastic intensities of Rayleigh scatteringof Moessbauer radiation were measured for lysozyme and myoglobin (fordifferent degrees of hydration: from h = 0.05 till h = 0.7). The treating ofthe data at h > 0.05 approves the existence of segmental motions(α-helices for myoglobin, α-helices and β-sheets forlysozyme) as well as of individual motions. Further hydration increase themean-square displacements for both types of intraglobular motions for theseproteins, while the motions of the globule as a whole remain nearlythe same as for h = 0.05. Results of the study of the radial distributionfunction deduced by Fourier - transform from the diffuse x-raymeasurements together with RSMR data allow to conclude that the waterduring hydration of proteins competes with the intramolecular hydrogenbonds, loosens the protein and increases the internal dynamics. At the sametime water arranges the ordering of macromolecule from `glassy' state ath ≈ 0.02 to the native state at h = 0.4-0.7. Differentarchitecture of proteins leads to the different structural dynamics as in thecase of lysozyme and myoglobin.
N.N. Semenov Institute of Chemical Physics, RAS, 117977 Moscow, Russia.
Yu F
YF
Krupyanskii
S V
SV
Esin
G V
GV
Eshenko
M G
MG
Mikhailyuk
Rayleigh scattering of Moessbauer radiation; diffuse x-ray scattering; dynamics; hydration; lysozyme; myoglobin