Catalyzes the activation of long-chain fatty acids as acyl-adenylates (acyl-AMP), which are then transferred to a multifunctional polyketide synthase (PKS) for further chain extension. ATP + dodecanoate + H(+) = diphosphate + dodecanoyl-AMP Lipid metabolism; fatty acid biosynthesis. Belongs to the ATP-dependent AMP-binding enzyme family.