Variable Assembly and Procapsid Binding of Bacteriophage P22 Terminase Subunits in Solution.

ABSTRACT: Concatemeric viral DNA is packaged into bacteriophage P22 procapsids via a headful packaging mechanism mediated by a molecular machine consisting of small (gp3) and large (gp2) terminase subunits. Although a negative stain reconstruction exists for the terminase holoenzyme, it is not clear how this complex binds the dodecameric portal protein located at a 5-fold mismatch vertex. Herein, we describe new assemblies for the holoenzyme. Both native mass spectrometry and transmission electron microscopy reveal that the P22 terminase complex adopts three main assemblies, which include a nonameric S-terminase bound to two L-terminase 1(gp3)₉:2(gp2), two nonameric S-terminase bound to five L-terminase 2(gp3)₉:5(gp2), and three nonameric S-terminase bound to seven L-terminase

SUBMITTER: Cabral JE 

PROVIDER: S-EPMC11728703 | biostudies-literature | 2024 Dec

REPOSITORIES: biostudies-literature