Fig 5. Residence times of single membrane-targeted FtsZ molecules at the bilayer, dependent on nucleotide and free Mg²⁺.

(A) Overlaid images of FtsZ-YFP-mts structures (yellow channel) incubated with GFP-Booster-Atto647N (nanobody) (single molecules: red channel) in the presence of GTP (a, b), GDP (c, d), and indicated free Mg²⁺ concentration. The protein concentration in all cases was around 0.2 μM. (B) Mean residence times of FtsZ-YFP-mts were calculated using an exponential fit of the cumulative residence time distribution. Mean residence times were measured for different GTP and Mg²⁺ conditions. Further details under Materials and methods and Results. GDP, guanosine diphosphate; GFP, green fluorescent protein; GTP, guanosine triphosphate; mts, membrane-targeting sequence; YFP, yellow fluorescent protein.