Fig. 1
From: Structures of T7 bacteriophage portal and tail suggest a viral DNA retention and ejection mechanism
Structure of the T7 bacteriophage portal. a Ribbon representation of the gp8closed structure of the portal with rainbow coloring by monomer. The dimensions of the particle are indicated. Left, lateral view; right, axial view. b Ribbon representation of a monomer of the gp8closed structure, colored by domains, with relevant secondary structure elements and structural features indicated. c Electrostatic potential on the external (up) and inner channel (down) surfaces of the gp8closed portal. A thin positively charged channel ring, formed by R368, is indicated. d Detail of the superposition of gp8closed (blue ribbon) and gp8open structures (orange ribbon). The conformational change of the channel valve is indicated with an arrow and maximum torsion angle is shown. e Comparison of the two conformations by showing two opposed monomers. Left, closed conformation shown in blue ribbon. Right, open conformation shown in orange ribbon. The crown domain is not visible for the open conformation and has not been shown for the closed connector for the sake of clarity
