Figure 6. Proposed Mechanism of Primer Handoff Driven by DNA Charge Transport Chemistry.

DNA primase elongates an RNA primer (green) to 8–12 nt length with both p48 and p58C contacting the nascent RNA/DNA duplex (left). When the nascent primer is large enough, another [4Fe4S] enzyme (purple), which we hypothesize to be DNA polymerase αin vivo, participates in DNA-mediated signaling through the primer-template duplex (middle). This promotes dissociation of p58C through reduction of the cluster from the [4Fe4S]³⁺ state to the [4Fe4S]²⁺ state; the next [4Fe4S] enzyme is then tightly bound and can continue elongation of the primer-template (right).