Structure of the voltage-gated L-type Ca2+ channel by electron cryomicroscopy

Voltage-dependent L-type Ca2+ channels play important functional roles in many excitable cells. We present a three-dimensional structure of an L-type Ca2+ channel. Electron cryomicroscopy in conjunction with single-particle processing was used to determine a 30-Angstrom resolution structure of the channel protein. The asymmetrical channel structure consists of two major regions: a heart-shaped region connected at its widest end with a handle-shaped region. A molecular model is proposed for the arrangement of this skeletal muscle L-type Ca2+ channel structure with respect to the sarcoplasmic reticulum Ca2+-release channel, the physical partner of the L-type channel for signal transduction during the excitation-contraction coupling in muscle.