Fig. 2.

BT_0972 is an operative 3-KDSR in Bacteroides thetaiotaomicron. A: Scheme for enzymatic conversion of 3-ketosphinganine alkyne (3-KDS^alk) to sphinganine alkyne (SA^alk) catalyzed by 3-ketosphinganine reductase (3-KDSR). Ion chromatograms of (B) 3-KDS^alk and (C) SA^alk detected in B. thetaiotaomicron 3-KDSR candidates that were heterologously expressed in BL21 Escherichia coli. Quantification of (D) 3-KDS^alk and (E) SA^alk detected in B. thetaiotaomicron KDSR candidates that were heterologously expressed in BL21 E. coli. The Saccharomyces cerevisiae 3-KDSR (TSC10) was expressed in BL21 E. coli and used as a positive control for 3-KDSR activity. A synthetic SA^alk standard was used to detect SA^alk. (ND, not detected. n = 2 biological replicates per gene candidate and positive controls; representative traces are shown here.) 3-KDS^alk, 3-ketosphinganine alkyne; 3-KDSR, 3-ketosphinganine reductase; SA^alk, sphinganine alkyne.