Phosphorylation enhances PC4 mediated condensation of H1 bound array forming higher order structures. (A) Sedimentation velocity analysis by analytical ultracentrifugation of H1 bound to nucleosome array at 0.5 ratio (H1:NCP) with 1 uM of PM-PC4 (phosphomimic PC4) and PC4 (wild type unmodified recombinant). A nucleosome array without any any ectopic addition of protein was used as a control. (B) Sedimentation coefficient values from the panel A,at a boundary fraction of 50% (n = 3). Data represent the means ± SD.The S50%(S) were statistically analysed by ordinary one-way ANOVA, Sidak's multiple comparisons test as well as Student's paired t-test (*P< 0.05,**P< 0.01,***P< 0.001, ns, non-significant (C, D) EM images showing the overview of the structures formed upon PM-PC4 (phosphomimic PC4) (1 uM) and PC4 (wild type unmodified recombinant) (1 uM) mediated compaction of H1-array respectively. (E) Distribution of diameters (in um) of PM-PC4 (phosphomimic PC4) and PC4 (wild type unmodified recombinant) compacted H1 bound array particles. No. of particles measured = 132. Data represent the means ± SD. The S50%(S) were statistically analysed by Student's unpaired t-test (*P< 0.05,**P< 0.01,***P< 0.001,ns-non-significant). (F, G) The close up view showing the EM image of two H1 bound array compacted by 1uM of PM-PC4 and PC4 respectively.