A bacterial acetoacetyl-CoA synthetase directly activates acetoacetate with ATP and CoA.
"The enzyme absolutely required ATP, CoA, a monovalent cation (K+, Rb+, Cs+ or NH+4) and a divalent cation (Mg2+, Mn2+, Ca2+ or Ni2+) for the activation of acetoacetate, yielding acetoacetyl-CoA, AMP and pyrophosphate in equimolar amounts."