Related Experiment Video
Updated: Aug 10, 2026

Structure of HIV-1 Capsid Assemblies by Cryo-electron Microscopy and Iterative Helical Real-space Reconstruction
Published on: August 9, 2011
Crystal structures of two intermediates in the assembly of the papillomavirus replication initiation complex
Eric J Enemark1, Arne Stenlund, Leemor Joshua-Tor
1W.M.Keck Structural Biology Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
Abstract:
Initiation of DNA replication of the papillomavirus genome is a multi-step process involving the sequential loading of viral E1 protein subunits onto the origin of replication. Here we have captured structural snapshots of two sequential steps in the assembly process. Initially, an E1 dimer binds to adjacent major grooves on one face of the double helix; a second dimer then binds to another face of the helix. Each E1 monomer has two DNA-binding modules: a DNA-binding loop, which binds to one DNA strand and a DNA-binding helix, which binds to the opposite strand. The nature of DNA binding suggests a mechanism for the transition between double- and single-stranded DNA binding that is implicit in the progression to a functional helicase.
Related Concept Videos
Protein Complex Assembly
Many viruses self-assemble into a fully functional unit using the infected host cell to...
The DNA Replication Fork
The Replisome
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
Restarting Stalled Replication Forks
Formation of Intermediate Filaments
Inhibitors of Virion Maturation and Assembly

