Figure 6.

H4 tail acetylation changes the pK_a of H18, which in turn further informs ensemble characteristics. (A) ¹⁵N, ¹³C–CON spectra of unAc (left) and 5Ac (right) pH titrations. NMR experiments were performed in 50 mM K₂HPO₄, 150 mM KCl, with variable pH throughout the titration. (B) CSP vs pH fits for H18 in the unAc and 5Ac context. (C) Proton adjusted R_g probability distributions from MD simulations with average R_g values indicated. Errors of the R_g distributions are estimated using block averages with five blocks. (D) Mean fractions of total residues involved in the formation of various secondary structure elements calculated over three independent MD simulations for unAc, 5Ac, and protonated H18 of 5Ac. Error bars denote standard error of the mean. (E) Per residue difference in SASA from MD simulations, comparing the H18 protonated and deprotonated states. Errors represent the standard error of the mean calculated over three independent MD simulations.