A Synthetic S6 Segment Derived from KvAP Channel Self-assembles, Permeabilizes Lipid Vesicles, and Exhibits Ion Channel Activity in Bilayer Lipid Membrane

• DOI: 10.1074/jbc.m110.209676
• Publication Date: 2011-05-19T00:18:18Z
• Authors: Richa Verma; Chetan Malik; Sarfuddin Azmi; Saurabh Srivastava; Subhendu Ghosh; Jimut Kanti Ghosh
• Keywords: Calcein; Phosphatidylglycerol

KvAP is a voltage-gated tetrameric K(+) channel with six transmembrane (S1-S6) segments in each monomer from the archaeon Aeropyrum pernix. The objective of present investigation was to understand plausible role S6 segment, which has been proposed form inner lining pore, membrane assembly and functional properties channel. For this purpose, 22-residue peptide, corresponding segment (amino acids 218-239), scrambled peptide (S6-SCR) rearrangement only hydrophobic amino but without changing its composition were synthesized characterized structurally functionally. Although both peptides bound negatively charged phosphatidylcholine/phosphatidylglycerol model comparable affinity, significant differences observed between these their localization, self-assembly, aggregation onto membrane. S6-SCR also exhibited reduced helical structures SDS micelles lipid vesicles as compared peptide. Furthermore, showed membrane-permeabilizing capability evidenced by release calcein calcein-entrapped vesicles, whereas much weaker efficacy. Interestingly, although ion activity bilayer membrane, despite having same acid composition, significantly inactive. results demonstrated sequence-specific structural wild type selected probably an important element that could play interaction, assembly, property