文章基本信息

标题：The β₂ clamp in the Mycobacterium tuberculosis DNA polymerase III αβ₂ε replicase promotes polymerization and reduces exonuclease activity
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作者：Shoujin Gu ; Wenjuan Li ; Hongtai Zhang 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2016
卷号：6
DOI：10.1038/srep18418
出版社：Springer Nature
摘要：DNA polymerase III (DNA pol III) is a multi-subunit replication machine responsible for the accurate and rapid replication of bacterial genomes, however, how it functions in Mycobacterium tuberculosis ( Mtb ) requires further investigation. We have reconstituted the leading-strand replication process of the Mtb DNA pol III holoenzyme in vitro , and investigated the physical and functional relationships between its key components. We verify the presence of an αβ₂ε polymerase-clamp-exonuclease replicase complex by biochemical methods and protein-protein interaction assays in vitro and in vivo and confirm that, in addition to the polymerase activity of its α subunit, Mtb DNA pol III has two potential proofreading subunits; the α and ε subunits. During DNA replication, the presence of the β₂ clamp strongly promotes the polymerization of the αβ₂ε replicase and reduces its exonuclease activity. Our work provides a foundation for further research on the mechanism by which the replication machinery switches between replication and proofreading and provides an experimental platform for the selection of antimicrobials targeting DNA replication in Mtb .