Tuzikov F V, Zinov'ev V V, Vavilin V I, Malygin E G, Ankilova V N
Mol Biol (Mosk). 1988 Nov-Dec;22(6):1623-31.
The method of small-angle X-ray scattering was employed to analyse the equilibrium enzyme-substrate complexes in solution. A new approach of analysis of the experimental data was developed. This type of analysis provides the determination of dissociation constants and structural parameters of enzyme-substrate complexes. The radius of gyration (Rg) and dimensions of half-axis of the equivalent prolonged ellipsoid (a, b) of E. coliphenylalanyl-tRNA synthetase and its complexes with one or two tRNA(Phe) molecules have been determined. The values of these parameters speak in favour of structural rearrangements due to the interaction of the enzyme with tRNA(Phe). The thermodynamic characteristics of phenylalanyl-tRNA synthetase complexes with tRNA(Phe) testify to the negative cooperativity in binding of two tRNA molecules with the enzyme.
采用小角X射线散射法分析溶液中的平衡酶-底物复合物。开发了一种新的实验数据分析方法。这种分析类型可确定酶-底物复合物的解离常数和结构参数。已测定大肠杆菌苯丙氨酰-tRNA合成酶及其与一个或两个tRNA(Phe)分子的复合物的回转半径(Rg)和等效延长椭球体半轴尺寸(a,b)。这些参数值表明由于酶与tRNA(Phe)的相互作用导致了结构重排。苯丙氨酰-tRNA合成酶与tRNA(Phe)复合物的热力学特征证明了两个tRNA分子与该酶结合时存在负协同性。
