Synthesis of a photoaffinity labeling analogue of the inactivating peptide of the Shaker B potassium channel

• Published in: FEBS letters 1996-11, Vol.398 (1), p.81-86
• Main Authors: Fernandez, Asia M., Molina, Antonio, Encinar, Jose A., Gavilanes, Francisco, López-Barneo, José, Gonzalez-Ros, Jose M.
• Format: Article
• Language: English
• Subjects: Affinity Labels - chemical synthesis; Affinity Labels - chemistry; Amino Acid Sequence; Animals; Azides - chemistry; Binding Sites; CHO Cells - metabolism; Cricetinae; Inactivating peptide, conformation; Ion channel inactivation; Molecular Sequence Data; Peptides - chemistry; Peptides - metabolism; Photoactivatable peptide analog; Photoaffinity labeling; Photolysis; Potassium Channels - drug effects; Potassium Channels - metabolism; Protein Conformation; Shaker Superfamily of Potassium Channels; Solutions
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(96)01186-6

A photoactivatable derivative of the inactivating peptide of the Shaker B potassium channel (ShB peptide) has been synthesized from ShB peptide containing an added cysteine residue at the peptide carboxy-terminus and 1-( p-azidosalicylamido)-4-(iodoacetamido)butane. The peptide derivative restores rapid inactivation in the deletion mutant Shaker BΔ6–46 potassium channel in a manner indistinguishable from that of the wild-type ShB peptide. Also, both peptides display similar conformational behavior when challenged in vitro by an artificial model target that partly imitates the properties of the putative receptor site for the inactivating peptide in the Shaker B potassium channel. Therefore, we conclude that both functionally and conformationally the photoreactive peptide derivative is an adequate analogue of the wild-type ShB peptide, suitable for photoaffinity labeling of its binding site in the Shaker B potassium channel. Moreover, because the ShB peptide also serves as an efficient inactivating peptide for a large variety of other potassium channels, it appears that the photoreactive analogue may be useful to explore homologous sites in many different channel proteins.