Importation of long-chain fatty acids by FadL and FadD. Long chain fatty acids (LCFAs) in the extracellular space are imported by the action of FadL protein into the periplasmic space. Due to the low pH, LCFAs are are protonated. FadD adds a CoA moiety to the carboxyl group, which facilitates the transport of LCFAs into the cytosol