Structure and dynamics of intact and premature filamentous bacteriophage viruses

Bacteriophage viruses have recently seen a revival in interest due to their potential use as anti-bacterial agents. Filamentous phage have been studied for many years due to interest spanning many fields of science including nano- and bio-technology applications.

Despite extensive studies, methods to produce high-resolution structures and filamentous phage have only come to age in the last 15 years. We will show how those advances have enabled us to determine the atomic-resolution structure of the M13 and IKe bacteriophages, the former by magic-angle spinning solid-state NMR, and the latter by cryo-electron microscopy. Recently, we have been applying NMR also to study a pre-mature form of the fd bacteriophage, when complexed with gene V protein (gVp), a non-structural protein that caps the ssDNA molecule inside the E.coli host cell. We will show how solid-state NMR can be used to verify the complexation of the protein with ssDNA extracted from intact phage, and how this technique provides an average protein-sheet – DNA distance. Moreover, it will be demonstrated that despite numerous structures of isolated gVp in solution and in crystalline state, when complexed with the ssDNA the protein undergoes structural changes. Those must be accounted for when attempting docking modelling of such systems.

The methods we present for structure characterization, protein-DNA contact studies and DNA conformational studies are applicable to vast number of bacteriophages and other viruses.