Lycopene elongases and C50 cyclases function in the C50-to-C60 pathway. (a–g) HPLC chromatogram of carotenoid extracts from E. coli cells expressing genes for C50-phytoene production with indicated genes. The indicated peak numbers correspond with those in Fig. 1. Peaks labelled with asterisks correspond to unidentified non-carotenoid compounds. (h) Absorbance spectra of the indicated peaks.