Fig. 2: PKS TR phylogeny, catalysis and crystal structures.
From: A polyketide-based biosynthetic platform for diols, amino alcohols and hydroxy acids
a, Phylogenetic analysis of PKS TRs, PKS KRs, mammalian fatty acid synthases (mFASs), NRPS R domains and ADHs in primary metabolism. The scale bar labeled ‘1.00’ means that a branch length of that size corresponds to one amino acid substitutions per site on average. b, TR9-catalysed reaction of a natural substrate mimic, octanoyl-ACP9. c,d, Characterization of the TR9 substrate scope and cofactor preference with NADPH (c) and NADH (d). NAD(P)H consumption was assessed by monitoring the UV absorbance at 340 nm. Black, TR9 + NAD(P)H + octanoyl-ACP9; blue,TR9 + NAD(P)H + octanoyl-CoA; brown, TR9 + NAD(P)H + octanal; green, NAD(P)H + octanoyl-CoA; orange, NAD(P)H + octanal. For TR catalysis, the preferred substrates are ACPs or CoAs and the preferred cofactor is NADPH. e, Crystal structure of the CpkC TR (TR1) bound to NADP+. The protein is shown in grey and the cofactor is shown in light blue (carbon), red (oxygen), dark blue (nitrogen) and orange (phosphorus). f, View of the active site of TR1 and Arg1824- and Arg1834-coordinated NADP+ ribose 2′-phosphate. Tyr1956 is the catalytic proton donor. The NADP+ omit map (mFo − DFc, 3.0 σ level) is shown in green. mFo represents the experimentally observed structure factors, DFc represents the calculated structure factors.
