This domain is found at the C-terminal of FakA (fatty acid subunit A) proteins, which is part of the fatty acid kinase machinery [1]. In the human pathogens Staphylococcus and Streptococcus, this system is used to scavenge host fatty acids. FakA is an ATP-binding subunit which interacts with varied FakB (fatty acid-binding protein) isoforms and synthesises acyl-phosphate from extracellular fatty acids [1]. FakA comprises three domains (FakA_N, FakA_M and FakA_C) and resembles an evolutionary mimic of the DhaK-DhaL kinase system. This entry represents FakA_C, which acts as a recipient of fatty acids transferred from FakB in the context of Fak activity [1].

1: Structure and mechanism for streptococcal fatty acid kinase (Fak) system dedicated to host fatty acid scavenging. Shi Y, Zang N, Lou N, Xu Y, Sun J, Huang M, Zhang H, Lu H, Zhou C, Feng Y; Sci Adv. 2022;8:eabq3944. PMID:36054360