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. Anal yses by CD and two-dimensional H-1 NMR spectroscopy were used to investigat e the structure of the peptide bound to SDS micelles in solution, which are commonly used in biophysical studies. The tertiary structure of the peptid e as a monomer was composed of an a-helix (431-438), a turn (439-442), and random coils (427-430, 443-452), and was very similar to that of the pore f orming region of the native K+ channel from Streptomyces lividans determine d 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 o n its intrinsic amino acid sequence and the surrounding environment. (C) 20 01 Elsevier Science B.V. All rights reserved.