2i05
Escherichia Coli Replication Terminator Protein (Tus) Complexed With TerA DNAEscherichia Coli Replication Terminator Protein (Tus) Complexed With TerA DNA
Structural highlights
Function[TUS_ECOLI] Trans-acting protein required for termination of DNA replication. Binds to DNA replication terminator sequences (terA to terF) to prevent the passage of replication forks. The termination efficiency will be affected by the affinity of this protein for the terminator sequence. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedDuring 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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