Solution structure of micelle-bound H5 peptide (427–452): a primary structure corresponding to the pore forming region of the voltage dependent potassium channel

A 26-mer peptide with the sequence of the pore forming region (residues 427–452) of the Shaker K+ channel (H5 region) was chemically synthesized. Analyses by CD and two-dimensional 1H NMR spectroscopy were used to investigate the structure of the peptide bound to SDS micelles in solution, which are commonly used in biophysical studies. The tertiary structure of the peptide as a monomer was composed of an α-helix (431–438), a turn (439–442), and random coils (427–430, 443–452), and was very similar to that of the pore forming region of the native K+ channel from Streptomyces lividans determined by X-ray analysis [1]. This result suggests that even an isolated peptide forms a native-like conformation for residues from 431 to 442, depending on its intrinsic amino acid sequence and the surrounding environment.