Nucleotide and receptor density modulate binding of bacterial division FtsZ protein to ZipA containing lipid-coated microbeads
Abstract
9 p.-6 fig. ; ZipA protein from Escherichia coli is one of the essential components of the division proto-ring that provides membrane tethering to the septation FtsZ protein. A sedimentation assay was used to measure the equilibrium binding of FtsZ-GDP and FtsZ-GTP to ZipA immobilized at controlled densities on the surface of microbeads coated with a phospholipid mixture resembling the composition of E. coli membrane. We found that for both nucleotide-bound species, the amount of bound FtsZ exceeds the monolayer capacity of the ZipA immobilized beads at high concentrations of free FtsZ. In the case of FtsZ-GDP, equilibrium binding does not appear to be saturable, whereas in the case of FtsZ-GTP equilibrium binding appears to be saturable. The difference between the two modes of binding is attributed to the difference between the composition of oligomers of free FtsZ-GDP and free FtsZ-GTP formed in solution. ; This work was supported by the Spanish government through grants BFU2014-52070-C2-2-P and BFU2016-75471-C2-1-P (to G.R.). G.R. is member of the CIB Intramural Program 'Macromolecular Machines for Better Life' (MACBET). Research of A.P.M. is supported by the Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases, NIH. ; Peer reviewed
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