A prokaryotic acyl-CoA reductase performing reduction of fatty acyl-CoA to fatty alcohol

► A prokaryotic enzyme (Maqu_2220) is shown to reduce fatty acyl-CoA to fatty alcohol. ► Maqu_2220 can utilize a broad range of acyl-CoA as substrates. ► Maqu_2220 can utilize ACP bound acyl chain as substrate. ► Homologous sequences to Maqu_2220 are found in a narrow range of prokaryotic genera. ► Amino acid sequences homologous to Maqu_2220 are found widely among eukaryotes. The reduction of acyl-CoA or acyl-ACP to fatty alcohol occurs via a fatty aldehyde intermediate. In prokaryotes this reaction is thought to be performed by separate enzymes for each reduction step while in eukaryotes these reactions are performed by a single enzyme without the release of the intermediate fatty aldehyde. However, here we report that a purified fatty acyl reductase from Marinobacter aquaeolei VT8, evolutionarily related to the fatty acyl reductases in eukaryotes, catalysed both reduction steps. Thus, there are at least two pathways existing among prokaryotes for the reduction of activated acyl substrates to fatty alcohol. The Marinobacter fatty acyl reductase studied has a wide substrate range in comparison to what can be found among enzymes so far studied in eukaryotes.