6t8o
Stalled FtsK motor domain bound to dsDNA end
Structural highlights
FunctionFTSK_PSEAE Essential cell division protein that coordinates cell division and chromosome segregation. The N-terminus is involved in assembly of the cell-division machinery. The C-terminus functions as a DNA motor that moves dsDNA in an ATP-dependent manner towards the dif recombination site, which is located within the replication terminus region. Translocation stops specifically at Xer-dif sites, where FtsK interacts with the Xer recombinase, allowing activation of chromosome unlinking by recombination. FtsK orienting polar sequences (KOPS) guide the direction of DNA translocation. FtsK can remove proteins from DNA as it translocates, but translocation stops specifically at XerCD-dif site, thereby preventing removal of XerC and XerD from dif (Probable).[1] [2] Publication Abstract from PubMedFtsK protein contains a fast DNA motor that is involved in bacterial chromosome dimer resolution. During cell division, FtsK translocates double-stranded DNA until both dif recombination sites are placed at mid cell for subsequent dimer resolution. Here, we solved the 3.6-A resolution electron cryo-microscopy structure of the motor domain of FtsK while translocating on its DNA substrate. Each subunit of the homo-hexameric ring adopts a unique conformation and one of three nucleotide states. Two DNA-binding loops within four subunits form a pair of spiral staircases within the ring, interacting with the two DNA strands. This suggests that simultaneous conformational changes in all ATPase domains at each catalytic step generate movement through a mechanism related to filament treadmilling. While the ring is only rotating around the DNA slowly, it is instead the conformational states that rotate around the ring as the DNA substrate is pushed through. FtsK in motion reveals its mechanism for double-stranded DNA translocation.,Jean NL, Rutherford TJ, Lowe J Proc Natl Acad Sci U S A. 2020 Jun 23;117(25):14202-14208. doi:, 10.1073/pnas.2001324117. Epub 2020 Jun 8. PMID:32513722[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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