Segrosome assembly at the pliable parH centromere

Meiyi Wu, Massimiliano Zampini, Malte Bussiek, Christian Hoischen, Stephan Diekmann, Finbarr Hayes

    Research output: Contribution to journalArticlepeer-review

    Abstract

    The segrosome of multiresistance plasmid TP228 comprises ParF, which is a member of the ParA ATPase superfamily, and the ParG ribbon-helix-helix factor that assemble jointly on the parH centromere. Here we demonstrate that the distinctive parH site (∼100-bp) consists of an array of degenerate tetramer boxes interspersed by AT-rich spacers. Although numerous consecutive AT-steps are suggestive of inherent curvature, parH lacks an intrinsic bend. Sequential deletion of parH tetramers progressively reduced centromere function. Nevertheless, the variant subsites could be rearranged in different geometries that accommodated centromere activity effectively revealing that the site is highly elastic in vivo. ParG cooperatively coated parH: proper centromere binding necessitated the protein's N-terminal flexible tails which modulate the centromere binding affinity of ParG. Interaction of the ParG ribbon-helix-helix domain with major groove bases in the tetramer boxes likely provides direct readout of the centromere. In contrast, the AT-rich spacers may be implicated in indirect readout that mediates cooperativity between ParG dimers assembled on adjacent boxes. ParF alone does not bind parH but instead loads into the segrosome interactively with ParG, thereby subtly altering centromere conformation. Assembly of ParF into the complex requires the N-terminal flexible tails in ParG that are contacted by ParF. © 2011 The Author(s).
    Original languageEnglish
    Pages (from-to)5082-5097
    Number of pages15
    JournalNucleic acids research.
    Volume39
    Issue number12
    DOIs
    Publication statusPublished - Jul 2011

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