Bennett P B, Makita N, George A L
Department of Pharmacology, Vanderbilt University Medical School, Nashville, TN 37232-2171.
FEBS Lett. 1993 Jul 12;326(1-3):21-4. doi: 10.1016/0014-5793(93)81752-l.
Recombinant sodium channel alpha subunits expressed in Xenopus oocytes display an anomalously slow rate of inactivation that arises from channels that predominantly exist in a slow gating mode [1,2]. Co-expression of Na+ channel beta 1 subunit with the human skeletal muscle Na+ channel alpha subunit increases the Na+ current and induces normal gating behavior in Xenopus laevis oocytes. The effects of the beta 1 subunit can be explained by an allosterically induced conformational switch of the alpha subunit protein that occurs upon binding the beta 1 subunit. This binding alters the free energy barriers separating distinct conformational states of the channel. The results illustrate a fundamental modulation of ion channel gating at the molecular level, and specifically demonstrate the importance of the beta 1 subunit for gating mode changes of Na+ channels.
在非洲爪蟾卵母细胞中表达的重组钠通道α亚基表现出异常缓慢的失活速率，这是由主要以缓慢门控模式存在的通道引起的[1,2]。将Na⁺通道β1亚基与人骨骼肌Na⁺通道α亚基共表达可增加Na⁺电流，并在非洲爪蟾卵母细胞中诱导正常的门控行为。β1亚基的作用可以通过与β1亚基结合时α亚基蛋白的变构诱导构象转换来解释。这种结合改变了分隔通道不同构象状态的自由能垒。这些结果说明了离子通道门控在分子水平上的基本调节，并特别证明了β1亚基对Na⁺通道门控模式变化的重要性。
