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. Author manuscript; available in PMC: 2021 Jan 1.
Published in final edited form as: Metab Eng. 2019 Nov 28;57:193–202. doi: 10.1016/j.ymben.2019.11.009

Figure 4.

Figure 4.

Efficient production of hexa-acylated MPLA is achieved by overexpression of LpxL and LpxM along with leaky expression of LpxE. (a) Growth curves for KHSC0003/pBAD33.1-lpxEAA supplemented with or without IPTG. The strain was grown in LB medium containing ampicillin and chloramphenicol supplemented with 0 (no IPTG), 1 mM IPTG (IPTG 1x) at time 0 and 1 mM IPTG at time 0 and 12 hours (IPTG 2x) after dilution. Overexpression of LpxL and LpxM increases the growth rate of the strain. (b) TLC profiles of the lipids extracted from the engineered E. coli strains compared with those of GLA (lane 1). Total lipids extracted from KHSC0003/pBAD33.1-lpxEAA grew supplemented with 0 (lane 2), IPTG 1x (lane 3), and IPTG 2x (lane 4). Overexpression of LpxL and LpxM is required for efficient hexa-acylated MPLA production. (c) Growth curves for KHSC0003/pBAD33.1-lpxEAA supplemented with different concentrations of l-arabinose (Ara). The strain was grown in LB medium containing ampicillin, chloramphenicol, and IPTG supplemented with 0, 0.01, 0.1, 1 mM Ara. Overexpression of LpxE by 1 mM Ara caused a long lagging phase. (d) TLC profiles of the lipids extracted from the engineered E. coli strains compared with those of GLA (lane 1). Total lipids extracted from KHSC0003/pBAD33.1-lpxEAA grew supplemented with 0 (lane 2), 0.01 mM Ara (lane 3), 0.1 mM Ara (lane 4), and 1 mM Ara (lane 5) at time 0. The presence of 1 mM Ara caused a long lagging phase of the strain growth, and the strain grown in the presence of 1 mM IPTG barely produced MPLA. The presence of 0, 0.01, or 0.1 mM Ara does not affect MPLA production.