primosome

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primosome A complex of enzymes and additional proteins that associates with the DNA molecule to initiate DNA replication in prokaryotes, such as E. coli. Its chief component is a primase enzyme, responsible for synthesizing short single strands of RNA, which serve as primers for DNA polymerase (see polymerase). The primosome also contains a helicase enzyme, which unwinds the two strands of the DNA in readiness for replication.