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FtsK activities in Xer recombination, DNA mobilization and cell division involve overlapping and separate domains of the protein
Author(s) -
Bigot Sarah,
Corre Jacqueline,
Louarn JeanMichel,
Cornet François,
Barre FrançoisXavier
Publication year - 2004
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2004.04335.x
Subject(s) - biology , translocase , chromosome segregation , cell division , dna , mutant , recombination , point mutation , microbiology and biotechnology , transmembrane domain , genetics , chromosome , cell , gene , chromosomal translocation
Summary Escherichia coli FtsK is a multifunctional protein that couples cell division and chromosome segregation. Its N‐terminal transmembrane domain (FtsK N ) is essential for septum formation, whereas its C‐terminal domain (FtsK C ) is required for chromosome dimer resolution by XerCD‐ dif site‐specific recombination. FtsK C is an ATP‐dependent DNA translocase. In vitro and in vivo data point to a dual role for this domain in chromosome dimer resolution (i) to directly activate recombination by XerCD‐ dif and (ii) to bring recombination sites together and/or to clear DNA from the closing septum. FtsK N and FtsK C are separated by a long linker region (FtsK L ) of unknown function that is highly divergent between bacterial species. Here, we analysed the in vivo effects of deletions of FtsK L and/or of FtsK C , of swaps of these domains with their Haemophilus influenzae counterparts and of a point mutation that inactivates the walker A motif of FtsK C . Phenotypic characterization of the mutants indicated a role for FtsK L in cell division. More importantly, even though Xer recombination activation and DNA mobilization both rely on the ATPase activity of FtsK C , mutants were found that can perform only one or the other of these two functions, which allowed their separation in vivo for the first time.