Hello Simon Menanteau-Ledouble

The presence of several ter sites for each replication fork is necessary to ensure that replication termination occurs and indicates a sense of redundancy, supported by the highly conserved nature of ter sites and their highly specific cognate binding capabilities.

Please refer to the link attached below for more information.

https://proteopedia.org/wiki/index.php/Replication_termination_in_E._coli_and_B._subtilis

The ter elements are asymmetric patterns of DNA that act as protein binding sites. These elements are situated in the terminus region, approximately opposite the origin of replication. The binding of specific proteins to ter elements provides a trap for the proceeding replication fork, catching the replication fork as it passes. There are several ter elements responsible for stopping each replication fork, with each of these elements being specific for the fork passing in one direction only, that is, they have functional polarity. The ter-protein complex responsible for catching the clockwise replication fork will allow the anticlockwise fork to proceed unchecked, until it is stopped by its own anticlockwise facing ter element fork trap.

Replication fork traps have been identified in multiple species possessing circular chromosomes, including E. coli. Fork traps prevent over replication of the bacterial chromosome and stall a faster fork in the case that one side of the replication was proceeding faster than the other.

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