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Biochemistry. 2005 Jun 14;44(23):8230-43.

Secondary structure formation of a transmembrane segment in Kv channels.

Author information

1
Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6085, USA.

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.

PMID:
15938612
DOI:
10.1021/bi050372q
[Indexed for MEDLINE]

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