3zbq
Protofilament of TubZ from Bacteriophage PhiKZ
Structural highlights
FunctionPHUZ_BPDPK A tubulin-like GTPase that forms filaments, which are required for positioning viral DNA and capsids in the middle of the host cell for optimal replication. The motor component of a partition system which pushes phage DNA (encased by protein gp105) to the center of the bacterial host cell (PubMed:28813669). Also required for movement of phage capsids to the vicinity of the viral DNA and rotation of the encased viral DNA at midcell (PubMed:28813669). Forms filaments during the lytic phase, which position phage DNA at the center of the bacterial host cell (PubMed:28813669). Filaments have a three-stranded intertwined architecture and form a spindle-like cytoskeleton within the infected cell (PubMed:23528827). Has GTPase activity (Probable). Filaments grow at the plus end and depolymerize at the minus end, a process called treadmilling, and switch from growing in a polar manner to catastrophic depolymerization, i.e. they display dynamic instability, like tubulin (By similarity). In infected host cells the filament ends close to the cell pole are relatively stable, while the other end near the phage DNA is highly dynamic. Both capsid movement and DNA rotation probably require treadmilling (By similarity).[UniProtKB:B3FK34][1] [2] [3] Publication Abstract from PubMedPseudomonas PhiKZ-like bacteriophages encode a group of related tubulin/FtsZ-like proteins believed to be essential for the correct centring of replicated bacteriophage virions within the bacterial host. In this study, we present crystal structures of the tubulin/FtsZ-like protein TubZ from Pseudomonas bacteriophage PhiKZ in both the monomeric and protofilament states, revealing that PhiKZ TubZ undergoes structural changes required to polymerise, forming a canonical tubulin/FtsZ-like protofilament. Combining our structures with previous work, we propose a polymerisation-depolymerisation cycle for the Pseudomonas bacteriophage subgroup of tubulin/FtsZ-like proteins. Electron cryo-microscopy of PhiKZ TubZ filaments polymerised in vitro implies a long-pitch helical arrangement for the constituent protofilaments. Intriguingly, this feature is shared by the other known subgroup of bacteriophage tubulin/FtsZ-like proteins from Clostridium species, which are thought to be involved in partitioning the genomes of bacteriophages adopting a pseudo-lysogenic life cycle. Structure of the Tubulin/FtsZ-Like Protein TubZ from Pseudomonas Bacteriophage PhiKZ.,Aylett CH, Izore T, Amos LA, Lowe J J Mol Biol. 2013 Mar 22. pii: S0022-2836(13)00167-8. doi:, 10.1016/j.jmb.2013.03.019. PMID:23528827[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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