A phage tubulin assembles dynamic filaments by an atypical mechanism to center viral DNA within the host cell.
Tubulins are essential for the reproduction of many eukaryotic viruses, but historically, bacteriophage were assumed not to require a cytoskeleton. Here, we identify a tubulin-like protein, PhuZ, from bacteriophage 201φ2-1 and show that it forms filaments in vivo and in vitro. The PhuZ structure has a conserved tubulin fold, with an unusual, extended C terminus that we demonstrate to be critical for polymerization in vitro and in vivo. Longitudinal packing in the crystal lattice mimics packing observed by EM of in-vitro-formed filaments, indicating how interactions between the C terminus and the following monomer drive polymerization. PhuZ forms a filamentous array that is required for positioning phage DNA within the bacterial cell. Correct positioning to the cell center and optimal phage reproduction only occur when the PhuZ filament is dynamic. Thus, we show that PhuZ assembles a spindle-like array that functions analogously to the microtubule-based spindles of eukaryotes.
Department of Biochemistry and Biophysics and the Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
James A
JA
Kraemer
Marcella L
ML
Erb
Christopher A
CA
Waddling
Elizabeth A
EA
Montabana
Elena A
EA
Zehr
Hannah
H
Wang
Katrina
K
Nguyen
Duy Stephen L
DS
Pham
David A
DA
Agard
Joe
J
Pogliano
D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000502:physiology*; D003599:Cytoskeleton / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011549:Pseudomonas / Q000166:cytology / Q000821:virology*; D016415:Sequence Alignment; D014404:Tubulin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D004279:DNA, Viral; D014404:Tubulin; D014764:Viral Proteins; D006153:Guanosine Diphosphate