Single-Molecule Imaging of Ion Channels Isolated in Detergent and Styrene-Maleic Acid Copolymer

In this work we purified Shaker ion channel using two alternative techniques – the detergent-based (CHAPS) and styrene-maleic acid copolymer lipid particles (XIRAN-based). Using XIRAN-based technique, we can obtain higher yield of purified protein. We used atomic force microscopy and transmission electron microscopy methods to visualize the purified single molecules. Atomic force microscopy allows measuring the diameter of the single molecules but does not reveal any high-resolution details. The sizes of individual Shaker molecules isolated by the two purification methods were close to each other.