2i06
From Proteopedia
Escherichia Coli Replication Terminator Protein (Tus) Complexed With DNA- Locked form
Overview
During chromosome synthesis in Escherichia coli, replication forks are blocked by Tus bound Ter sites on approach from one direction but not the other. To study the basis of this polarity, we measured the rates of dissociation of Tus from forked TerB oligonucleotides, such as would be produced by the replicative DnaB helicase at both the fork-blocking (nonpermissive) and permissive ends of the Ter site. Strand separation of a few nucleotides at the permissive end was sufficient to force rapid dissociation of Tus to allow fork progression. In contrast, strand separation extending to and including the strictly conserved G-C(6) base pair at the nonpermissive end led to formation of a stable locked complex. Lock formation specifically requires the cytosine residue, C(6). The crystal structure of the locked complex showed that C(6) moves 14 A from its normal position to bind in a cytosine-specific pocket on the surface of Tus.
About this Structure
2I06 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
A molecular mousetrap determines polarity of termination of DNA replication in E. coli., Mulcair MD, Schaeffer PM, Oakley AJ, Cross HF, Neylon C, Hill TM, Dixon NE, Cell. 2006 Jun 30;125(7):1309-19. PMID:16814717 Page seeded by OCA on Sun May 4 06:55:08 2008
