Characterization of the in vitro assembly of FtsZ in Arthrobacter strain A3 using light scattering

The self-assembly of FtsZ, the bacterial homolog of tubulin, plays an essential role in cell division. Light scattering technique is applied to real-time monitor the in vitro assembly of FtsZ in Arthrobacter strain A3, a newly isolated psychrotrophic bacterium. The critical concentration needed for the assembly is estimated as 6.7 μM. The polymerization of FtsZ in Arthrobacter strain A3 requires both GTP and divalent metal ions, while salt is an unfavorable condition for the assembly. The FtsZ polymerizes under a wide range of pHs, with the fastest rate around pH 6.0. The FtsZ from Arthrobacter strain A3 resembles Mycobacterium tuberculosis FtsZ in terms of the dependence on divalent metal ions and the slow polymerization rate, while it is different from M. tuberculosis FtsZ considering the sensitivity to salt and pH. The comparison of FtsZ from different organisms will greatly advance our understanding of the biological role of the key cell division protein.