毒丝菌素对单体肌动蛋白结构和动力学的影响。
The effect of toxofilin on the structure and dynamics of monomeric actin.
作者信息
Czimbalek Lívia, Kollár Veronika, Kardos Roland, Lőrinczy Dénes, Nyitrai Miklós, Hild Gábor
机构信息
University of Pécs, Medical School, Department of Biophysics, Pécs, Szigeti Str. 12, H-7624, Hungary.
University of Pécs, Medical School, Department of Biophysics, Pécs, Szigeti Str. 12, H-7624, Hungary; Szentágothai Research Center, Pécs, Ifjúság Str. 34, H-7624, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Pécs, Szigeti Str. 12, H-7624, Hungary.
出版信息
FEBS Lett. 2015 Oct 7;589(20 Pt B):3085-9. doi: 10.1016/j.febslet.2015.08.038. Epub 2015 Sep 5.
The effects of toxofilin (an actin binding protein of Toxoplasma gondii) on G-actin was studied with spectroscopy techniques. Fluorescence anisotropy measurements proved that G-actin and toxofilin interact with 2:1 stoichiometry. The affinity of toxofilin to actin was also determined with a fluorescence anisotropy assay. Fluorescence quenching experiments showed that the accessibility of the actin bound ε-ATP decreased in the presence of toxofilin. The results can be explained by the shift of the nucleotide binding cleft into a closed conformational state. Differential scanning calorimetry measurements revealed that actin monomers become thermodynamically more stable due to the binding of toxofilin.
利用光谱技术研究了弓形虫肌动蛋白结合蛋白毒丝菌素对G-肌动蛋白的影响。荧光偏振测量证明，G-肌动蛋白和毒丝菌素以2:1的化学计量比相互作用。还通过荧光偏振测定法确定了毒丝菌素对肌动蛋白的亲和力。荧光猝灭实验表明，在毒丝菌素存在下，与肌动蛋白结合的ε-ATP的可及性降低。结果可以通过核苷酸结合裂隙转变为封闭构象状态来解释。差示扫描量热法测量表明，由于毒丝菌素的结合，肌动蛋白单体在热力学上变得更稳定。
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