In voltage-gated ion channels, transmembrane segments S3 and S4 are involved in voltage sensing and adopt a helix-turn-helix conformation, called the paddle motif, in crystal structures. Now extensive mutagenesis and electrophysiology analyses of the Shaker K+ channel demonstrate the physiological relevance of the paddle motif and dissect the roles of each segment in voltage sensing.
- Yanping Xu
- Yajamana Ramu
- Zhe Lu