19 February 1999
Vol 283, Issue 5405

About The Cover

Cover image expansion

COVER Gap junction membrane channels between adjacent cells allow passage of ions and small molecules that coordinate electrical and metabolic activities in tissues. In the heart such channels mediate current flow from cell to cell, thereby synchronizing the heartbeat. This density map of a cardiac gap junction channel (solid and mesh density; ~150 Å long) reveals 24 protein a helices (gold rods) spanning each cell membrane (white boxes). See page 1176.[Computer graphics: M. Pique and M. Yeager]