Silverman William R, Heginbotham Lise
Department of Molecular, Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, P.O. Box 208114, New Haven, CT 06520-8114, USA.
FEBS Lett. 2007 Oct 30;581(26):5024-8. doi: 10.1016/j.febslet.2007.09.017. Epub 2007 Sep 19.
Although the cyclic nucleotide-modulated potassium channel from Mesorhizobium loti, MlotiK1, is easily studied using a 86Rb+ flux assay, its comparatively low activity raises serious concerns about the integrity of the purified protein. We investigated the pathway of uptake using a multi-pronged approach. First, we probed the conduction pathway using quaternary ammonium compounds known to block conduction in eukaryotic K+ channels. Second, we examined the effect of chemical modification of putative pore-lining residues. Our results are consistent with ions traversing MlotiK1 along a conduction pathway like that of the eukaryotic channels, but at a much slower rate.
尽管来自百脉根中生根瘤菌的环核苷酸调节钾通道MlotiK1很容易通过⁸⁶Rb⁺通量测定法进行研究，但其相对较低的活性引发了对纯化蛋白完整性的严重担忧。我们采用多管齐下的方法研究了摄取途径。首先，我们使用已知可阻断真核生物K⁺通道传导的季铵化合物探测传导途径。其次，我们研究了假定的孔内衬残基化学修饰的影响。我们的结果表明，离子沿着类似于真核生物通道的传导途径穿过MlotiK1，但速度要慢得多。
