Summary information and primary citation
- PDB-id
-
4xr2;
DSSR-derived features in text and
JSON formats
- Class
- replication-DNA
- Method
- X-ray (2.35 Å)
- Summary
- Escherichia coli replication terminator protein (tus)
h114a mutant complexed with DNA- tera lock.
- Reference
-
Elshenawy MM, Jergic S, Xu ZQ, Sobhy MA, Takahashi M,
Oakley AJ, Dixon NE, Hamdan SM (2015): "Replisome
speed determines the efficiency of the Tus-Ter
replication termination barrier." Nature,
525, 394-398. doi: 10.1038/nature14866.
- Abstract
- In all domains of life, DNA synthesis occurs
bidirectionally from replication origins. Despite variable
rates of replication fork progression, fork convergence
often occurs at specific sites. Escherichia coli sets a
'replication fork trap' that allows the first arriving fork
to enter but not to leave the terminus region. The trap is
set by oppositely oriented Tus-bound Ter sites that block
forks on approach from only one direction. However, the
efficiency of fork blockage by Tus-Ter does not exceed 50%
in vivo despite its apparent ability to almost permanently
arrest replication forks in vitro. Here we use data from
single-molecule DNA replication assays and structural
studies to show that both polarity and fork-arrest
efficiency are determined by a competition between rates of
Tus displacement and rearrangement of Tus-Ter interactions
that leads to blockage of slower moving replisomes by two
distinct mechanisms. To our knowledge this is the first
example where intrinsic differences in rates of individual
replisomes have different biological outcomes.
