Structural studies on bacterial carotenoids and their biosynthetic implications

Abstract

Detailed studies of the properties of carotenoids isolated from diphenylamine-inhibited cultures of Rhodospirillum rubrum have revealed a number of novel structures which indicate new features of carotenoid biosynthesis in the photosynthetic bacteria. The dehydrogenation of phytoene to coloured carotenoids occurs by a sequence which is different from that in higher plants in that 7,8,11,12-tetrahydrolycopene, rather than ξ-carotene, is the immediate precursor of neurosporene. Both neurosporene and 7,8,11,12-tetrahydrolycopene undergo hydration, methylation and dehydrogenation to yield spheroidene and 11', 12'-dihydrospheroidene respectively; all the intermediates in these pathways have been identified. These pathways represent alternative routes of anhydrorhodovibrin and spirilloxanthin biosynthesis. © 1969, Walter de Gruyter. All rights reserved.