Heterologous expression of a cardiomyopathic myosin that is defective in its actin interaction.
Heterologous expression of a cardiomyopathic myosin that is defective in its actin interaction.
复制标题
心肌病肌球蛋白的异源表达，其肌动蛋白相互作用有缺陷。
DOI：
10.1016/s0021-9258(17)42067-9
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
L. Faust
中科院分区：
文献类型：
--
作者：
H. Sweeney;A. Straceski;L. Leinwand;B. Tikunov;L. Faust
心肌肌球蛋白重链中的点突变导致精氨酸 (Arg) 被谷氨酰胺 (Gln) 取代，与人类肥厚型心肌病有关（Geisterfer-Lowrance, A. A. T.、Kass, S.、Tanikawa, G.、Vosberg, H.-P.、McKenna, W.、Seidman, J. G. 和 Seidman, C. E. (1990) 细胞 62, 999-1006)。为了确定这种突变的功能影响，杆状病毒驱动的肌球蛋白重链和轻链共表达已经被开发出来。 Arg-403→Gln 突变导致心肌肌球蛋白在缺乏肌动蛋白的情况下具有正常的 ATP 酶活性。然而，在肌动蛋白存在的情况下，ATPase 活性大大降低（Vmax 降低 > 3.5 倍，K(app) 增加 > 3 倍）。这种单一氨基酸突变使体外运动能力降低了近 5 倍。因此，Arg-403 可能有助于肌球蛋白肌动蛋白界面的重要相互作用。用 Gln 替代 Arg-403 会导致肌动蛋白-肌球蛋白跨桥循环内的转变速率降低。在人类中，这种突变将导致心肌单位面积的功率输出减少，可能会刺激心肌肥大。
A point mutation in the heavy chain of cardiac myosin, resulting in replacement of an arginine (Arg) with glutamine (Gln), has been linked to hypertrophic cardiomyopathy in humans (Geisterfer-Lowrance, A. A. T., Kass, S., Tanigawa, G., Vosberg, H.-P., McKenna, W., Seidman, J. G., and Seidman, C. E. (1990) Cell 62, 999-1006). To determine the functional impact of this mutation, baculovirus-driven coexpression of myosin heavy and light chains has been developed. The Arg-403–>Gln mutation resulted in cardiac myosin with normal ATPase activity in the absence of actin. However, in the presence of actin, ATPase activity was greatly reduced (Vmax decreased > 3.5-fold and K(app) increased > 3-fold). In vitro motility was reduced nearly 5-fold by this single amino acid mutation. Thus, Arg-403 likely contributes to an important interaction at the actin interface of myosin. Replacement of Arg-403 with Gln leads to decreased rate(s) of transition within the actin-myosin crossbridge cycle. In humans, this mutation will result in decreased power output per unit area of cardiac muscle, likely providing a stimulus for hypertrophy.