PDBsum entry 3hef

Viral protein

PDB id: 3hef

Contents

Protein chains

123 a.a.

130 a.a.

Waters ×254

References listed in PDB file

Key reference

• Title: Crystal structure of the DNA-Recognition component of the bacterial virus sf6 genome-Packaging machine.
• Authors: H.Zhao, C.J.Finch, R.D.Sequeira, B.A.Johnson, J.E.Johnson, S.R.Casjens, L.Tang.
• Ref.: Proc Natl Acad Sci U S A, 2010, 107, 1971-1976.
• PubMed id: 20133842

Abstract

In herpesviruses and many bacterial viruses, genome-packaging is a precisely mediated process fulfilled by a virally encoded molecular machine called terminase that consists of two protein components: A DNA-recognition component that defines the specificity for packaged DNA, and a catalytic component that provides energy for the packaging reaction by hydrolyzing ATP. The terminase docks onto the portal protein complex embedded in a single vertex of a preformed viral protein shell called procapsid, and pumps the viral DNA into the procapsid through a conduit formed by the portal. Here we report the 1.65 A resolution structure of the DNA-recognition component gp1 of the Shigella bacteriophage Sf6 genome-packaging machine. The structure reveals a ring-like octamer formed by interweaved protein monomers with a highly extended fold, embracing a tunnel through which DNA may be translocated. The N-terminal DNA-binding domains form the peripheral appendages surrounding the octamer. The central domain contributes to oligomerization through interactions of bundled helices. The C-terminal domain forms a barrel with parallel beta-strands. The structure reveals a common scheme for oligomerization of terminase DNA-recognition components, and provides insights into the role of gp1 in formation of the packaging-competent terminase complex and assembly of the terminase with the portal, in which ring-like protein oligomers stack together to form a continuous channel for viral DNA translocation.