Gene sll0033 from Synechocystis 6803 encodes a carotene isomerase involvedin the biosynthesis of all-E lycopene

The function of gene sll0033 from Synechocystis 6803 which is homologous to the bacterial crtI-type phytoene desaturase genes was elucidated as a nove l carotene isomerase. Escherichia coli transformed with all genes necessary for the. formation of zeta -carotene and expressing a zeta -carotene desat urase synthesized the positional isomer prolycopene (7,9,7',9'Z lycopene) w hich cannot be cyclized in the subsequent reactions to a- and beta -caroten e. Upon cotransformation with sll0033, the formation of all-E lycopene is m ediated instead.