2nd Midlands Biophysics Symposium at University of Nottingham
Assembly and bundling of the bacterial Z-ring protein FtsZ
The bacterial cell division protein FtsZ is a homologue of eukaryotic tubulins that polymerizes in a GTP-dependent manner. On this poster, we present our assessment of FtsZ polymerization and its dynamic behaviour in real time by right angle light scattering using a spectrophotometer. Polymerization was very rapid, remaining constant for about 5 minutes. The final phase of the reaction is a fast decrease in light scattering, indicating net depolymerisation occurred as the GTP in the reaction has all been converted to GDP. The effects of GTP, pH, K+, and Mg2+ on FtsZ polymerization were studied as well. The length of the steady-state phase was proportional to the GTP concentration, and importantly, Mg2+ was required for GTP hydrolysis, but not for GTP binding. The second part of the poster shows the kinetics of inorganic phosphate (Pi) released from the GTP hydrolysis. The assay employs a fast and sensitive spectrophotometric assay that measures ¦¡¡¡¡¡ì¬¡¡¡¡ì¬A360 between the substrate MESG (2-amino-6-mercapto-7-methylpurine riboside) and the products (ribose 1-phosphate and 2-amino-6-mercapto-7-methlpurine). At pH 6.5, approximate 90% of the Pi was released into the media within around 20 minutes of GTP addition. The effects of GTP, pH, K+, and Mg2+ were also studied, and they are consistent with the previous results.