Combined analytical ultracentrifugation, light scattering and fluorescence spectroscopy studies on the functional associations of the bacterial division FtsZ protein

► FtsZ self- and hetero-associations described by orthogonal biophysical approaches. ► Protein polymer molar mass measured by thermodynamic and hydrodynamic methods. ► GTP-FtsZ polymers in close to physiological buffers are formed by 100-140 monomers. ► Protein interactions in nanodiscs studied by sedimentation and fluorescence assays. ► ZipA in nanodiscs binds FtsZ oligomers and polymers with equal moderate affinity.