PhD ThesisSepF is identified as a late cell division protein which is conserved
among Gram-positive bacteria. It was shown that SepF also has a positive role
in formation of FtsZ filaments. Moreover, SepF forms rings by itself and tubules
with FtsZ in vitro. Here, it is shown that ring formation is conserved. Several
SepF orthologs was purified and studied with electron microscopy. Most of
these SepF orthologs polymerized and some of them formed clear rings that are
similar to SepF rings of Bacillus subtilis. Furthermore, the C-terminal domain of
SepF is sufficient to form SepF rings. The crystal structure of this domain
revealed that it forms tight dimers which polymerize through interactions
between α-helices. Yeast-two-hybrid studies of SepF mutants showed that the
C-terminal domain of SepF is also required for FtsZ interaction. The analysis of
the N-terminus of SepF both in vitro and in vivo revealed an amphipathic helix
which is crucial for the function of SepF. This study showed that similar to FtsA,
SepF anchors FtsZ to the cell membrane. A second project, called Bacillus
Minimal Divisome, revealed the core division proteins which are sufficient to
initiate the cell division
