María I Daudén / Jaime Martín-Benito / Juan C Sánchez-Ferrero / Mar Pulido-Cid / José M Valpuesta / José L Carrascosa /
PubMed 要旨
During bacteriophage morphogenesis DNA is translocated into a preformed prohead by the complex formed by the portal protein, or connector, plus the terminase, which are located at an especial prohead ...During bacteriophage morphogenesis DNA is translocated into a preformed prohead by the complex formed by the portal protein, or connector, plus the terminase, which are located at an especial prohead vertex. The terminase is a powerful motor that converts ATP hydrolysis into mechanical movement of the DNA. Here, we have determined the structure of the T7 large terminase by electron microscopy. The five terminase subunits assemble in a toroid that encloses a channel wide enough to accommodate dsDNA. The structure of the complete connector-terminase complex is also reported, revealing the coupling between the terminase and the connector forming a continuous channel. The structure of the terminase assembled into the complex showed a different conformation when compared with the isolated terminase pentamer. To understand in molecular terms the terminase morphological change, we generated the terminase atomic model based on the crystallographic structure of its phage T4 counterpart. The docking of the threaded model in both terminase conformations showed that the transition between the two states can be achieved by rigid body subunit rotation in the pentameric assembly. The existence of two terminase conformations and its possible relation to the sequential DNA translocation may shed light into the molecular bases of the packaging mechanism of bacteriophage T7.
EMDB-2355: Negative staining three dimensional reconstruction of bacteriophage T7 large terminase PDB-4bij: Threading model of T7 large terminase 手法: EM (単粒子) / 解像度: 16.0 Å
EMDB-2356: Negative staining three-dimensional reconstruction of bacteriophage T7 connector/terminase complex PDB-4bil: Threading model of the T7 large terminase within the gp8gp19 complex 手法: EM (単粒子) / 解像度: 29.0 Å
由来
enterobacteria phage t7 (ファージ)
キーワード
HYDROLASE / ATPASE / DNA TRANSLOCATION / SINGLE-PARTICLE RECONSTRUCTION / PACKAGING MOTOR / CONNECTOR / ATPASE.