Fig. 3
Functional analysis of EhDH domains in Escherichia coli (E. coli). a Complementation plate assay of the dehydratase (DH) domains in E. coli FabA Temperature-sensitive (Ts) mutant. DH domains were individually inserted behind the inducing promoter pBAD. The transformants grown on 0.02% L-arabinose selection plates were incubated overnight at 30 and 37 ℃, respectively. FabA, E. coli wild type dehydratase; TcDH1-DH2, the mutant expresses tandem DH1-DH2 domains from Thraustochytrium; Mutant, E. coli FabA Ts mutant with an empty vector; EhDH1, the mutant expresses the DH1 domains from Emiliania huxleyi; EhDH2, the mutant expresses the EhDH2 domains; EhDH1-DH2, the mutant expresses both EhDH1 and EhDH2. b The amount of fatty acid production in E. coli expressing the DH domains. Fatty acid production in E. coli Rosetta strains overexpressing DH domains. EV, E. coli Rosetta with an empty vector; EhDH1, E. coli Rosetta overexpressing EhDH1 domain; EhDH2, E. coli Rosetta overexpressing EhDH2 domain; EhDH1-DH2, E. coli Rosetta overexpressing both EhDH1 and EhDH2; TcDH1-DH2, E. coli Rosetta overexpressing both TcDH1 and TcDH2. Fatty acid abbreviations are the following: 14:0, myristic acid; 16:0, palmitic acid; 16:1, palmitoleic acid; 18:0, octadecanoic acid; 18:1, cis-vaccenic acid; SFAs saturated fatty acids, UFAs unsaturated fatty acids, Total total fatty acids. Values are reported as the means ± standard deviation of three independent biological replicates. Means with the same letters do not differ significantly. Statistical analysis of the results was conducted using one-way analysis of variance (P < 0.05)