RT Journal Article
SR Electronic
T1 Mechanistic Origins of Dynamic Instability in Filaments from the Phage Tubulin, PhuZ
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 311498
DO 10.1101/311498
A1 Zehr, Elena A.
A1 Rohu, Alexis
A1 Liu, Yanxin
A1 Verba, Kliment A.
A1 Pogliano, Joe
A1 Grigorieff, Nikolaus
A1 Agard, David A.
YR 2018
UL http://biorxiv.org/content/early/2018/04/30/311498.abstract
AB A bacteriophage-encoded tubulin homologue, PhuZ, harnesses dynamic instability to position genomes of ՓKZ-like bacteriophage at the midline of their Pseudomonas hosts, facilitating phage infectivity. While much has been learned about molecular origins of microtubule dynamics, how GTP binding and hydrolysis control dynamics in the divergent 3-stranded PhuZ filaments is not understood. Here we present cryo-EM reconstructions of the PhuZ filamentin a pre-hydrolysis (3.5Å) and three post-hydrolysis states (4.2 Å, 7.3 Å and 8.1 Å resolutions), likely representing distinct depolymerization stages. Core polymerization-induced structural changes reveal similarities to αβ-tubulin, suggesting broad conservation within the tubulin family. By contrast, GTP hydrolysis is sensed quite differently and is communicated by the divergent PhuZ C-terminus to the lateral interface, leading to PhuZ polymer destabilization. This provides a contrasting molecular description of how nucleotide state can be harnessed by the tubulin fold to regulate filament assembly, metastability and disassembly.