Figure 2. Acetylation is important for binding of δ and ε subunits as well as overall complex stability.

(A) A typical mass spectrum of the naturally modified cATPase. The intact F1 and the complex that had lost the δ subunit are present in solution. Dissociation products are generated in the gas-phase due to loss of ε. (B) After treatment with a deacetylase (SIRT3) two more complexes that have lost the ε subunit are present in solution. Gas-phase dissociation products are generated by loss of ε and δ subunits. Intensities of dissociation products are increased.