Ese genes are more closely related to those in filamentous cyanobacteria than the other -carotene-containing Prochlorococcus species.2008 www.pnas.org cgi doi 10.1073 pnas.A. marina is the only cyanobacterium found to contain both cruA and cruP, responsible for - and -carotene synthesis, in addition to lycopene cyclase (crtL) (35, 36). One class of cyclase, CrtL-e for -cyclase, was identified as t