FtsZ_(Dr), a tubulin homologue in radioresistant bacterium Deinococcus radiodurans is characterized as a GTPase exhibiting polymerization/depolymerization dynamics in vitro and FtsZ ring formation in vivo

摘要

The GTPase-dependent polymerization/depolymerization dynamics of FtsZ regulate bacterial cell division in vivo. Deinococcus radiodurans is better known for its extraordinary radioresistance and therefore, the characterization of FtsZ of this bacterium (FtsZ_(Dr)) would be required to understand the mechanisms underlying regulation of cell division in response to DNA damage. Recombinant FtsZ_(Dr) bound to GTP and showed GTPase activity. It produced bundles of protofilaments in the presence of either GTP or Mg~(2+) ions. But the formation of the higher size ordered structures required both GTP and Mg~(2+) in vitro. It showed polymerization/depolymerization dynamics as a function of GTP and Mg~(2+). Interestingly, ATP interacted with FtsZ_(Dr) and stimulated its GTPase activity by ~2-fold possibly by increasing both substrate affinity and rate of reaction. FtsZ_(Dr)-GFP expressing in D. radiodurans produced typical Z ring perpendicular to the plane of first cell division. These results suggested that FtsZ_(Dr) is a GTPase in vitro and produces typical Z ring at the mid cell position in D. radiodurans.