Gordon L G, Haydon D A
Biochim Biophys Acta. 1976 Jul 1;436(3):541-56. doi: 10.1016/0005-2736(76)90439-9.
It is already well-established that conduction in lipid bilayers containing alamethicin arises from the presence of complexes in which there are several molecules of the polypeptide. It is with the nature of these complexes that this paper is primarily concerned. While it is clear that increasing alamethicin concentration and increasing potential across the membrane favour their formation, the nature of the reactions involved has not yet been elucidated. Attempts have therefore been made to clarify the sequence of events leading to the establishment of a complex in its conducting state. It has been concluded that the most likely mechanism involves, initially, a non-field-dependent aggregation of the alamethicin, in the plane of the membrane, into non-conducting oligomers. These then appear to undergo movement normal to the membrane (which is field dependent) to form the conducting species. Temperature studies have shown that the various conducting states of the oligomer have effectively equal enthalpies, and that the activation energies for transitions between these states are all approx. 1.2kcal/mol. The corresponding rate constants are very sensitive to the lipid composition of the membrane and a variety of different systems has been examined in order to clarify the origins of this effect. The only conclusion from this part of the work is that lipid fluidity might be involved.
业已充分证实，在含有阿拉米辛的脂质双分子层中，传导源于存在含有多个多肽分子的复合物。本文主要关注的就是这些复合物的性质。虽然很明显，增加阿拉米辛浓度和跨膜电位有利于它们的形成，但所涉及反应的性质尚未阐明。因此，人们试图阐明导致复合物形成其传导状态的一系列事件。得出的结论是，最可能的机制最初涉及阿拉米辛在膜平面内非场依赖性聚集形成非传导性低聚物。然后这些低聚物似乎会发生垂直于膜的移动（这是场依赖性的）以形成传导性物质。温度研究表明，低聚物的各种传导状态具有实际上相等的焓，并且这些状态之间转变的活化能均约为1.2千卡/摩尔。相应的速率常数对膜的脂质组成非常敏感，并且已经研究了各种不同的系统以阐明这种效应的起源。这项工作这一部分唯一的结论是可能涉及脂质流动性。
