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. 2018 Jan 2;13(1):e0189892. doi: 10.1371/journal.pone.0189892

Fig 5. Reconstruction of the carotenoid biosynthesis transcriptional units.

Fig 5

(A) A schematic of carotenoid biosynthetic pathway showing the enzymes mediating the production of zeaxanthin as the final product. (B) The multi-TU constructs made by Mobius Assembly to produce lycopene (crtEBI) and β-carotene (crtEBIY) (in Level 2 Acceptor Vectors) and for zeaxanthin (crtEBIYZ) by assembling crtEBIY and crtZ back in a Level 1 A Vector. Colonies producing lycopene are pink (C), β-carotene orange (D), and zeaxanthin yellow (E). Cells carrying intact Level 2 Vectors produced bright yellow colonies, and Level 1 Vectors pink colonies. Gel electrophoresis of the PCR from five colonies (pink, orange and yellow from each cloning, respectively) verified the correct size of the constructs; 4.3kb for lycopene (F), 5.7kb for β-carotene (G), and 6.7kb zeaxanthin (H). UV-Visible spectrophotometry showed expected peaks for lycopene (446nm, 472nm, and 503nm, I), β-carotene (450nm and 478nm, J) and zeaxanthin (450nm and 478nm, K).