Dynamic assembly, disassembly and bundling of the bacterial cell division protein FtsZ and YgfE (ZapA)
Cheng, Xi, Ph.D. (2011) Dynamic assembly, disassembly and bundling of the bacterial cell division protein FtsZ and YgfE (ZapA). PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b2581619~S1
The protein FtsZ is a tubulin-like GTPase, which plays an essential role in
prokaryotic cell division. In vivo it assembles into a dynamic ring (the Z-ring) at the
future site of cell division on the inner surface of the cytoplasmatic membrane. The
Z-ring then serves as a scaffold which recruits all other division proteins to form the
cytokinetic machinery. The constriction of the ring facilitates the separation of two
In vitro, FtsZ polymerizes in the presence of GTP to form single-stranded
protofilaments. It is assumed that FtsZ association and assembly reactions studied in
vitro will play an important role in understanding the mechanism of Z-ring assembly
and disassembly in vivo. In this work, we therefore have studied the dynamics of
FtsZ polymerization in vitro, especially the bundling induced with YgfE.
YgfE, the putative Escherichia coli ZapA orthologue, is one of these division
proteins recruited by FtsZ. It acts to enhance lateral associations between FtsZ fibres
to form larger bundles. In this study, we have demonstrated that YgfE exists as a
tetramer in solution at the concentrations reported in this study, and the bundling
activity is exerted more efficiently on preformed FtsZ protofilaments. We also
investigate the importance of the tetramerisation of YgfE on function. A number of
mutant forms of ZapA were generated with the aim of disrupting the dimer:dimer
interface. Using those mutants we show that tetramerisation is a requirement for
both FtsZ bundling, and GTPase modulation activities.
In addition, a novel technique, continuous channel flow linear dichroism (LD)
spectroscopy, has been first developed in this work. LD is a simple spectroscopy
technique for structural characterization of long biomacromolecules in solutions.
Continuous channel flow Flow LD has overcome the limitation of Couette flow LD
due to the time required to assemble and fill the cell.
|Item Type:||Thesis or Dissertation (PhD)|
|Subjects:||Q Science > QR Microbiology|
|Library of Congress Subject Headings (LCSH):||Prokaryotes -- Physiology, Cell division, Guanosine triphosphatase|
|Official Date:||December 2011|
|Institution:||University of Warwick|
|Theses Department:||Department of Chemistry|
|Supervisor(s)/Advisor:||Rodger, Alison ; Hicks, Matthew ; Roper, David I.|
|Extent:||xv, 188,  leaves : ill., charts|
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