©2004, Elsevier
(A) shows the conventional topology of a voltage-gated potassium channel subunit with six transmembrane domains (S1–S6). Charge carrying residues are indicated on the S4 (red) segment. (B) shows the KvAP crystal structure. (C) shows the conventional model of voltage sensor movement. Depolarization moves the extracellular portion of the S4 segment outward, opening the permeation pathway. In (D), the paddle model, depolarization moves the paddle, the S3b helix, and the extracellular end of the S4 segment outward through lipid, pulling the cytoplasmic activation gate open. (From C.A. Ahern, R. Horn, Trends Neurosci, 27:303–7, June, 2004.)
The ion channel field has been a bit charged up lately, thanks largely to an impressive series of crystalline structures published by Rod MacKinnon's group at Rockefeller University.12345 While nearly all these structures have been the subjects of highly cited papers, this month's Hot papers12 were the subject of controversy right from the start. ...
