γ-氨基-ATP使肌球蛋白亚片段1稳定处于高荧光状态。
Gamma-amido-ATP stabilizes a high-fluorescence state of myosin subfragment 1.
作者信息
Wray John, Jahn Werner
机构信息
Abteilung Biophysik, Max-Planck-Institut für Medizinische Forschung, Jahnstr. 29, 69120, Heidelberg, Germany.
出版信息
FEBS Lett. 2002 May 8;518(1-3):97-100. doi: 10.1016/s0014-5793(02)02654-6.
On binding to myosin subfragment 1 (S1), the gamma-amido derivative of ATP (ATPgammaNH2), an isomer of adenosine 5'-[beta,gamma-imido]-triphosphate (AMPPNP), induces a larger increase in the intrinsic (tryptophan) fluorescence than is seen with ATP. A binding constant of 1.7x10(7) M(-1) was measured for ATPgammaNH2, compared to 2.1-2.4x10(7) M(-1) for AMPPNP. ATPgammaNH2 was hydrolyzed only very slowly by S1. ATPgammaNH2 appears to stabilize the 'closed' conformation of S1, and does so without cleavage of the beta-gamma phosphate bond. The dissociation of actin-S1 by ATPgammaNH2 and that of S1.ATPgammaNH2 by actin are both strikingly slow.
与肌球蛋白亚片段1（S1）结合时，ATP的γ-氨基衍生物（ATPγNH2），即腺苷5'-[β,γ-亚氨基]-三磷酸（AMPPNP）的异构体，比ATP诱导更大的内在（色氨酸）荧光增加。测得ATPγNH2的结合常数为1.7×10⁷ M⁻¹，而AMPPNP的结合常数为2.1 - 2.4×10⁷ M⁻¹。S1对ATPγNH2的水解非常缓慢。ATPγNH2似乎能稳定S1的“封闭”构象，且不会断裂β-γ磷酸键。ATPγNH2引起肌动蛋白-S1解离以及肌动蛋白引起S1.ATPγNH2解离都非常缓慢。
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