Korchev Y E, Bashford C L, Alder G M, Apel P Y, Edmonds D T, Lev A A, Nandi K, Zima A V, Pasternak C A
Department of Physiology, Charing Cross and Westminister Medical School, University of London, U.K.
FASEB J. 1997 Jun;11(7):600-8. doi: 10.1096/fasebj.11.7.9212084.
Fluctuation of ion current, between a high conductance and a low conductance state, through biological ion channels and pores is assumed to arise from conformational changes between an "open" and a "closed" configuration. Here we offer an additional mechanism that arises from changes in ionization of fixed charges within, or at the mouth of, a channel or pore. Our hypothesis, which is based on measurements of ion selectivity alongside ion current, applies to pores through some synthetic membranes and through channels-such as those created by certain toxins-that remain (at least partially) open in the low conductance state. It may also explain the phenomena of "open channel noise" and "substate behavior" that characterize several endogenous ion channels and should be considered when modeling the behavior of such channels.
通过生物离子通道和孔的离子电流在高电导状态和低电导状态之间的波动，被认为是由“开放”和“关闭”构型之间的构象变化引起的。在这里，我们提供了另一种机制，它源于通道或孔内部或口部固定电荷的电离变化。我们基于离子选择性与离子电流测量结果的假设，适用于一些合成膜中的孔以及某些毒素形成的通道——这些通道在低电导状态下（至少部分地）保持开放。它还可能解释表征几种内源性离子通道的“开放通道噪声”和“亚状态行为”现象，并且在对此类通道的行为进行建模时应予以考虑。
