Referenced in: none

Automatically associated channels: Kv1.3

Title: Secondary structure formation of a transmembrane segment in Kv channels.

Authors: Jianli Lu, Carol Deutsch

Journal, date & volume: Biochemistry, 2005 Jun 14 , 44, 8230-43

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/15938612

Abstract
Transmembrane segments in the intact voltage-gated potassium (Kv) channel are helical. To ascertain whether this helicity could first be manifested inside the ribosomal tunnel, we generated biogenic peptide intermediates of Kv1.3 and mass-tagged the cysteine-scanned S6 transmembrane segment using pegylation (PEG-MAL) and calmodulation (CaM-MAL). For reference, we created an extended peptide that was used as a "molecular tape measure" of the ribosomal tunnel and determined that the functional length of the tunnel is 99-112 A. We demonstrate that the S6 segment forms a compact structure inside the ribosomal tunnel and that the N-terminal half of S6 compacts more than the C-terminal half of S6. These results bear on the earliest folding events during biogenesis of ion channels.