4g80

Publication Abstract from PubMed

The transduction of transmembrane electric fields into protein motion has an essential role in the generation and propagation of cellular signals. Voltage-sensing domains (VSDs) carry out these functions through reorientations of positive charges in the S4 helix. Here, we determined crystal structures of the Ciona intestinalis VSD (Ci-VSD) in putatively active and resting conformations. S4 undergoes an ~5-A displacement along its main axis, accompanied by an ~60 degrees rotation. This movement is stabilized by an exchange in countercharge partners in helices S1 and S3 that generates an estimated net charge transfer of ~1 eo. Gating charges move relative to a hydrophobic gasket' that electrically divides intra- and extracellular compartments. EPR spectroscopy confirms the limited nature of S4 movement in a membrane environment. These results provide an explicit mechanism for voltage sensing and set the basis for electromechanical coupling in voltage-dependent enzymes and ion channels.

Structural mechanism of voltage-dependent gating in an isolated voltage-sensing domain.,Li Q, Wanderling S, Paduch M, Medovoy D, Singharoy A, McGreevy R, Villalba-Galea CA, Hulse RE, Roux B, Schulten K, Kossiakoff A, Perozo E Nat Struct Mol Biol. 2014 Mar;21(3):244-52. doi: 10.1038/nsmb.2768. Epub 2014 Feb, 2. PMID:24487958^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.