Crystal structure analysis of a fatty acid double‐bond hydratase from Lactobacillus acidophilus

摘要: Bacteria have evolved mechanisms for the hydrogenation of unsaturated fatty acids. Hydroxy acid formation may be first step in such a process; however, knowledge structural and mechanistic aspects this reaction is scarce. Recently, myosin cross-reactive antigen was shown to bacterial FAD-containing hydratase which acts on 9Z 12Z double bonds C16 C18 non-esterified acids, with 10-hydroxy 10,13-dihydroxy These hydratases form large protein family conserved across Gram-positive Gram-negative bacteria no sequence similarity any known apart from FAD-binding motif. In order shed light substrate recognition mechanism reaction, crystal structure Lactobacillus acidophilus (LAH) determined by single-wavelength anomalous dispersion. Crystal structures apo LAH bound linoleic were refined at resolutions 2.3 1.8 A, respectively. homodimer; each protomer consists four intricately connected domains. Three them substrate-binding sites reveal three domains several flavin-dependent enzymes, including amine oxidoreductases. The additional fourth domain located C-terminus α-helices. It covers entrance hydrophobic channel leading surface active site. presence acid, one undergoes conformational changes opens other homodimer. molecule channel, suggesting movement lid triggered recognition.