Disease relevance of Spirilloxanthin

• The apparent quantum yield of singlet-singlet spirilloxanthin-to-bacteriochlorophyll a energy transfer increases linearly with the residual spirilloxanthin content in Rhodospirillum rubrum membrane vesicles from which this carotenoid has been partially removed [1].
• In contrast to CrtC from Rvi. gelatinosus, the equivalent enzyme from Rhodobacter capsulatus, a closely related bacterium which lacks the biosynthetic branch to spirilloxanthin and accumulates spheroidene instead of substantial amounts of 1'-HO-spheroidene, is extremely poor in converting 1-HO-carotenoids [2].
• Although the tertiary methoxy group at C-1' and the double bond at C-3',4' in the psi end group of carotenoid, such as spirilloxanthin, have only been found in purple bacteria, this was the first such report in other bacterial groups [3].

High impact information on Spirilloxanthin

• We show that spirilloxanthin is associated with the photosynthetic complexes, while canthaxanthin protects the bacteria from oxidative stress [4].
• The target size of spirilloxanthin, 12 kDa, suggests that both polypeptides contribute to the binding site of this carotenoid [5].
• Substrate specificity of the expressed carotenoid 3,4-desaturase from Rubrivivax gelatinosus reveals the detailed reaction sequence to spheroidene and spirilloxanthin [6].
• Formation of the 3Bu state is observed for carotenoids in chromatophores, but not for in vitro spirilloxanthin indicating that the 3Bu state is formed by fission processes originating from the spatial organization of pigments within chromatophores [7].
• In both isolates (BH-1 and BH-2), the intracellular photosynthetic membranes are of the vesicular type and bacteriochlorophyll a and carotenoids of the normal spirilloxanthin series are present [8].

Biological context of Spirilloxanthin

• The operation of the EMBDEN-MEYERHOF pathway was confirmed by incorporation of 1-14C-, 3-14C-, and 6-14C-fructose into the spirilloxanthin fraction and analysis of its specific radioactivity [9].

References