LuxE is an acyl-protein synthetase found in bioluminescent bacteria. LuxE catalyzes the formation of an acyl-protein thioester from a fatty acid and a protein. This is the second step in the bioluminescent fatty acid reduction system, which converts tetradecanoic acid to the aldehyde substrate of the luciferase-catalyzed bioluminescence reaction A conserved cysteine found at position 364 in Photobacterium phosphoreum LuxE is thought to be acylated during the transfer of the acyl group from the synthetase subunit to the reductase. The carboxyl terminal of the synthetase is though to act as a flexible arm to transfer acyl groups between the sites of activation and reduction. This family also includes Vibrio cholerae RBFN protein, which is involved in the biosynthesis of the O-antigen component 3-deoxy-L-glycero-tetronic acid.