08 July 1988
Vol 241, Issue 4862

About The Cover

The gramicidin pore. The molecular structure (yellow) of the gramicidin pore is superimposed on a section of the electron density map derived from gramicidin/cesium crystals. The higher density contours (magenta) correspond to the ion ligands (cesiums and chlorides) located in the center of the pore. The lower density (blue) contours are from the polypeptide chains. See page 182. [B. A. Wallace and K. Ravikumar, Rensselaer Polytechnic Institute, Troy, NY 12180-3590]