Soultanas P, Dillingham M S, Papadopoulos F, Phillips S E, Thomas C D, Wigley D B
Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK andSchool of Biochemistry and Molecular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK.
Nucleic Acids Res. 1999 Mar 15;27(6):1421-8. doi: 10.1093/nar/27.6.1421.
The replication initiator protein RepD encoded by the Staphylococcus chloramphenicol resistance plasmid pC221 stimulates the helicase activity of the Bacillus stearothermophilus PcrA DNA helicase in vitro. This stimulatory effect seems to be specific for PcrA and differs from the stimulatory effect of the Escherichia coli ribosomal protein L3. Whereas L3 stimulates the PcrA helicase activity by promoting co-operative PcrA binding onto its DNA substrate, RepD stimulates the PcrA helicase activity by increasing the processivity of the enzyme and enables PcrA to displace DNA from a nicked substrate. The implication of these results is that PcrA is the helicase recruited into the replisome by RepD during rolling circle replication of plasmids of the pT181 family.
由氯霉素抗性质粒pC221编码的复制起始蛋白RepD在体外刺激嗜热脂肪芽孢杆菌PcrA DNA解旋酶的解旋酶活性。这种刺激作用似乎对PcrA具有特异性，并且不同于大肠杆菌核糖体蛋白L3的刺激作用。L3通过促进PcrA协同结合到其DNA底物上来刺激PcrA解旋酶活性，而RepD则通过增加酶的持续合成能力来刺激PcrA解旋酶活性，并使PcrA能够从带切口的底物上置换DNA。这些结果表明，在pT181家族质粒的滚环复制过程中，PcrA是被RepD招募到复制体中的解旋酶。
