Catalyzes the activation of medium/long-chain fatty acids as acyl-adenylates (acyl-AMP), which are then transferred to the phosphopantetheine arm of the acyl carrier protein (ACP) Rv0100 (PubMed:22451903, PubMed:23625916). Can use octanoate (C8), decanoate (C10), dodecanoate (C12), tetradecanoate (C14) and hexadecanoate (C16), but not hexanoate (C6) (PubMed:22451903, PubMed:23625916). Long chain saturated fatty acids are the preferred substrates (PubMed:23625916). Cannot use coenzyme A to form acyl-CoA (PubMed:22451903, PubMed:23625916). a medium chain fatty acid + ATP + holo-[ACP] = a medium-chain fatty acyl-[ACP] + AMP + diphosphate a long-chain fatty acid + ATP + holo-[ACP] = a long-chain fatty acyl-[ACP] + AMP + diphosphate ATP + holo-[ACP] + octanoate = AMP + diphosphate + octanoyl-[ACP] ATP + decanoate + holo-[ACP] = AMP + decanoyl-[ACP] + diphosphate ATP + dodecanoate + holo-[ACP] = AMP + diphosphate + dodecanoyl-[ACP] ATP + holo-[ACP] + tetradecanoate = AMP + diphosphate + tetradecanoyl-[ACP] ATP + hexadecanoate + holo-[ACP] = AMP + diphosphate + hexadecanoyl-[ACP] Lipid metabolism; fatty acid metabolism. Homodimer. Repressed by CRP. Retains a single open conformational state for both the apo- and ligand-bound forms. Belongs to the ATP-dependent AMP-binding enzyme family. Was originally thought to be a fatty acyl-CoA ligase (FACL) (PubMed:19182784). However, although FadD10 has a primary sequence similar to FACLs, it is indeed a fatty acyl-AMP ligase (FAAL) that is only able to acylate an ACP (Rv0100) rather than coenzyme A (PubMed:22451903, PubMed:23625916).