The effects of the detergent LDAO on the carotenoid metabolism and growth of Rhodovulum sulfidophilum

Abstract

Carotenoids play an important role in the purple non-sulfur bacteria. In this work we show that addition of the zwitterionic detergent LDAO (lauryldimethylamine N-oxide) to the growth media of Rhodovulum sulfidophilum results in a drastic alteration of the carotenoid biosynthesis, leading to the accumulation of the precursor neurosporene instead of carotenoids of the spheroidene series. This is probably due to a specific inhibition of the hydroxylation of neurosporene either by direct inhibition of the hydroxylase or by disruption of a presumed carotenoid synthesis multienzyme complex coordinated by the crtK encoded protein. Neurosporene can be integrated into peripheral light harvesting complexes (LHII), and is capable of efficient singlet energy transfer, but the resulting LHII complexes show a reduced stability relative to those containing normal carotenoids.