Contents

09 June 1989
Vol 244, Issue 4909

About The Cover

The arrangement of the electron density in a tetragonal crystal of human serum albumin. Prominent features of the molecular packing arrangement are large (90 Å by 90 Å) solvent channels (shown in purple) that pass through the crystal parallel to the crystallographic c-axis. The unit cell and symmetry operations parallel to the c-axis are illustrated. See page 1195. [D. C. Carter et al., NASA, Space Sciences Laboratory, Code ES76, Marshall Space Flight Center, AL 35612]