Structural highlights
Function
TUBZ_CBCP 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).[UniProtKB:Q8KNP3][1] [2]
References
- ↑ Oliva MA, Martin-Galiano AJ, Sakaguchi Y, Andreu JM. Tubulin homolog TubZ in a phage-encoded partition system. Proc Natl Acad Sci U S A. 2012 Apr 26. PMID:22538818 doi:10.1073/pnas.1121546109
- ↑ Fuentes-Pérez ME, Núñez-Ramírez R, Martín-González A, Juan-Rodríguez D, Llorca O, Moreno-Herrero F, Oliva MA. TubZ filament assembly dynamics requires the flexible C-terminal tail. Sci Rep. 2017 Feb 23;7:43342. PMID:28230082 doi:10.1038/srep43342
