Membrane-mediated assembly of filamentous bacteriophage Pf1 coat protein.

Filamentous bacteriophage Pf1 assembles by a membrane-mediated process during which the viral DNA is secreted through the membrane while being encapsulated by the major coat protein. Neutron diffraction studies showed that in the virus most of the coat protein consists of two alpha-helical segments arranged end-to-end with an intervening mobile surface loop. Nuclear magnetic resonance studies of the coat protein in the membrane-bound form have shown that the secondary structure is essentially identical to that in the intact virus. A comparison indicates that during membrane-mediated viral assembly, while the secondary structure of the coat protein is largely conserved, its tertiary structure changes substantially.