Figure 13.

Functional analysis of Z-ISO in E. coli. E. coli encoding bacterial GGPPS, PSY, and maize PDS accumulate 9,15,9′-tri-cis-ζ-carotene and were additionally transformed with the genes denoted or empty vector (pCOLADuet-1) as a control, and carotenoids were extracted and analyzed by HPLC. Under dark culturing conditions, Z-ISO from Arabidopsis (AtZ-ISO1.1) and maize (ZmZ-ISO1.1) convert most of the 9,15,9′-tri-cis-ζ-carotene (Tri) to 9,9′-di-cis-ζ-carotene (Di). Panels on the right show nonfunctioning proteins: truncated versions of Z-ISO missing the C terminus, such as the product of the short Arabidopsis transcript (AtZ-ISO1.2), transcript from the zic 1-1 mutant (AtZ-ISO1.1M), and NnrU from a denitrifying bacterium, S. meliloti 1021. Peaks are labeled as in Figure 3. [See online article for color version of this figure.]