Replisomkomplex

Replisomkomplex, commonly referred to as the replisome in many languages, is a dynamic multiprotein machine that coordinates DNA replication at the replication fork. It assembles at origins of replication and progresses with the fork as the double helix is unwound and copied. Its core function is to separate the two DNA strands, synthesize complementary new strands, and maintain high processivity and fidelity during genome duplication.

In bacteria, the replisome centers on the DnaB helicase, which unwinds DNA, the primase DnaG that lays RNA primers, and the DNA polymerase III holoenzyme that carries out most of the synthesis. The clamp loader (gamma complex) and the beta sliding clamp increase processivity, while single-strand DNA-binding proteins stabilize the unwound templates. Topoisomerases relieve torsional stress ahead of the fork.

In archaea and eukaryotes, the helicase is the CMG complex (Cdc45-MCM2-7-GINS), supported by DNA polymerases alpha-primase, delta, and epsilon. The sliding clamp is PCNA, operated by the RFC clamp loader. The replisome coordinates leading- and lagging-strand synthesis, the latter often via Okazaki fragments and trombone model looping, with ligases sealing nicks after primer removal.

Function and regulation: The replisome integrates the activities required for rapid, accurate genome duplication, coupling synthesis with proofreading and error repair. It is regulated by cell-cycle controls and DNA damage responses, and may be remodeled or disassembled during replication termination. Disruption of replisome function can lead to genome instability and disease. The term replisomkomplex is used in several languages to denote this complex; in English, the standard term is replisome.