(A) Organization of the carotenoid biosynthetic gene cluster of Pantoea ananatis. This cluster is composed of two transcriptional units; one is transcribed from PcrtE to crtE-crtX-crtY-crtI-crtB, and the other is PcrtZ-crtZ. (B) Carotenoid biosynthetic pathway. FPP, farnesyl pyrophosphate; IPP, isopentenyl diphosphate; GGPP, geranylgeranyl pyrophosphate; CrtE, GGPP synthase; CrtB, phytoene synthase; CrtI, phytoene desaturase; CrtY, lycopene cyclase; CrtZ, β-carotene hydroxylase; CrtX, zeaxanthin glucosyltransferase.
