Tubulin-like protein TubZ

UniProtKB accession:  Q331T7

Grouped By:  Matching UniProtKB accession

UniProtKB description:  A tubulin-like, filament forming GTPase; the motor component of the type III partition system presumably used to ensure correct segregation of this bacteriophage. In the presence of Mg(2+) and GTP (or GTP-gamma-S) assembles into filaments which upon polymerization are almost exclusively bound to GDP. Filament formation is cooperative, requiring a critical concentration. Formation occurs very quickly and is followed by disassembly as GTP is consumed. Unlike its plasmid homolog in B.thuringiensis (AC Q8KNP3) GTP-gamma-S does not alter filament formation (PubMed:22538818, PubMed:28230082). When forced to assemble with GDP instead of GTP it makes much stiffer, thicker filaments (PubMed:28230082). The filaments bind a DNA centromere-like site (tubC)-TubR complex which extends to surround the TubZ filaments (PubMed:22538818). Highly dynamic filaments grow at the plus end and depolymerize at the minus end, a process called treadmilling. TubR-tubC complexes track the depolymerizing minus end of the filament, probably pulling phage DNA within the cell (By similarity).