Krupyanskii Yu F, Esin S V, Eshenko G V, Mikhailyuk M G
N.N. Semenov Institute of Chemical Physics, RAS, 117977 Moscow, Russia.
J Biol Phys. 2002 Jun;28(2):139-45. doi: 10.1023/A:1019934304686.
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.
测量了溶菌酶和肌红蛋白(不同水合程度:从h = 0.05到h = 0.7)的穆斯堡尔辐射瑞利散射非弹性强度的角度依赖性。对h > 0.05的数据处理证实了存在片段运动(肌红蛋白的α螺旋,溶菌酶的α螺旋和β折叠)以及单个运动。进一步水合会增加这些蛋白质两种类型的球内运动的均方位移,而整个球状体的运动与h = 0.05时几乎相同。通过傅里叶变换从漫射X射线测量推导的径向分布函数的研究结果与RSMR数据一起表明,蛋白质水合过程中的水与分子内氢键竞争,使蛋白质松弛并增加内部动力学。同时,水将大分子的有序性从h≈0.02时的“玻璃态”排列到h = 0.4 - 0.7时的天然态。蛋白质的不同结构导致不同的结构动力学,如溶菌酶和肌红蛋白的情况。