CRYSTALLOGRAPHIC ANALYSIS REVEALS THE 12-FOLD SYMMETRY OF THE BACTERIOPHAGE-PHI-29 CONNECTOR PARTICLE

The internal symmetry of the connector or portal particle from the dou ble-stranded DNA bacteriophage phi 29 has been examined by X-ray cryst allography. This large multimeric structure (420 kDa) is built up by a number of identical subunits of the p10 protein. It connects the head of the virus with the tail and plays a central role in the prohead as sembly and DNA packaging. For the first time a bacteriophage connector has been crystallized and X-ray data have been collected up to a reso lution of 3.2 Angstrom. A self-rotation function has been calculated, unambigously revealing the 12-fold symmetry of the particle and its or ientation in the crystal lattice. The orientation has been confirmed b y calculating a cross-rotation function using a low resolution model b ased on electron microscopy reconstructions. (C) 1998 Academic Press.