31 May 1991
Vol 252, Issue 5010

About The Cover

A drawing of viral particle assembly at a membrane surface. Assembly of the filamentous bacteriophage Pfl takes place by the addition of coat protein subunits to the growing virus cylinder as the DNA extrudes through the host cell membrane without incorporating lipids. The coat protein undergoes a structural transition during his translocation process in which its secondary structure remains essentially unchanged while its tertiary structure changes substantially. See pages 1303 and 1305. [Drawing by L. Makowski]