Busath D D, Andersen O S, Koeppe R E
Biophys J. 1987 Jan;51(1):79-88. doi: 10.1016/S0006-3495(87)83313-1.
The relative frequency of low-conductance variants of gramicidin A channels in lipid bilayers was determined in parallel experiments in two different laboratories. A common gramicidin stock solution was tested in both labs and, initially, gave rise to significantly different proportions (9% v. 23%) of "mini" channels in the two labs. The lipid and gramicidin solutions were exchanged to identify the source of the difference: When using solutions prepared in lab A (Andersen), lab B (Busath) observed 9% minis, consistent with the original findings in lab A; when using the gramicidin solution prepared in lab B, lab A observed 18% minis, consistent with the original findings in lab B. The experimental apparatus and analysis techniques are therefore not the source of the discrepancy; rather, the difference appears to stem from some factor(s) related to the gramicidin, lipid, and electrolyte solutions. It appears that the mini frequency cannot reflect intrinsic characteristics of the channel-forming peptide, but rather must, at least in part, reflect environmental modulations of channel properties. This has implications for the interpretation of multi-channel experiments on gramicidin A.
在两个不同实验室的平行实验中，测定了脂双层中短杆菌肽A通道低电导变体的相对频率。在两个实验室中都测试了一种常见的短杆菌肽储备溶液，最初，两个实验室中“微型”通道的比例显著不同（9%对23%）。交换脂质和短杆菌肽溶液以确定差异来源：当使用在实验室A（安徒生）制备的溶液时，实验室B（布萨特）观察到9%的微型通道，与实验室A的原始结果一致；当使用在实验室B制备的短杆菌肽溶液时，实验室A观察到18%的微型通道，与实验室B的原始结果一致。因此，实验装置和分析技术不是差异的来源；相反，差异似乎源于与短杆菌肽、脂质和电解质溶液相关的某些因素。看来微型通道频率不能反映形成通道的肽的内在特性，而至少在一定程度上必须反映通道特性的环境调节。这对短杆菌肽A多通道实验的解释有影响。
