Changes of creatine kinase structure upon ligand binding as seen by small-angle scattering
Changes of creatine kinase structure upon ligand binding as seen by small-angle scattering
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DOI：
10.1016/s0022-2860(96)09289-7
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发表时间：
1996-09-30
影响因子：
3.8
通讯作者：
Wallimann, T
中科院分区：
文献类型：
--
作者：
Forstner, M;Kriechbaum, M;Wallimann, T
小角X射线和中子散射已被用来研究结构变化后，结合个别基板或过渡态类似物复合物（TSAC），包括镁-ADP，肌酸和硝酸钾肌酸激酶同工酶（二聚体M-CK和八聚体Mi-CK）和单体精氨酸激酶（AK）。在Mg-ATP和TSAC结合后，分子的形状和大小发生了相当大的变化，而单独的肌酸只有很小的影响。在Mi-CK中，回转半径从55.6埃（游离酶）减小到48.9埃（酶+ Mg-ATP）和48.2埃（酶+ TSAC）。用M-CK进行的实验显示出从28.0埃（游离酶）到25.6埃（酶+ Mg-ATP）和到25.5埃（酶+ TSAC）的类似变化。肌酸单独没有导致回转半径的显着变化，也没有游离ATP或ADP。AK表现出同样的行为：回转半径从21.5埃（游离酶）变化到19.7埃（酶+ MG-ATP），而单独使用精氨酸时仅观察到微小的变化。与单体AK所看到的结构的主要变化似乎是一个镁-核苷酸诱导的结构域相对于彼此的运动，而基板的效果可能是局部顺序。然而，在肌酸激酶中，进一步的运动必须参与大的构象变化。
Small-angle X-ray and neutron scattering have been used to investigate structural changes upon binding of individual substrates or a transition state analogue complex (TSAC), consisting of Mg-ADP, creatine and KNO3 to creatine kinase isoenzymes (dimeric M-CK and octameric Mi-CK) and monomeric arginine kinase (AK). Considerable changes in the shape and the size of the molecules occurred upon binding of Mg-ATP and TSAC, whereas creatine alone had only a small effect. In Mi-CK, the radius of gyration was reduced from 55.6 Angstrom (free enzyme) to 48.9 Angstrom (enzyme + Mg-ATP) and to 48.2 Angstrom (enzyme + TSAC). The experiments performed with M-CK showed similar changes from 28.0 Angstrom (free enzyme) to 25.6 Angstrom (enzyme + Mg-ATP) and to 25.5 Angstrom (enzyme + TSAC). Creatine alone did not lead to significant changes in the radii of gyration, nor did free ATP or ADP. AK showed the same behaviour: a change of the radius of gyration from 21.5 Angstrom (free enzyme) to 19.7 Angstrom (enzyme + MG-ATP), whereas with arginine alone only a minor change could be observed. The primary change in structure as seen with monomeric AK seems to be a magnesium-nucleotide induced domain movement relative to each other, whereas the effect of substrate may be of local order only. In creatine kinase, however, further movements must be involved in the large conformational change.