RESUMEN
From four strains of the gliding phototrophic bacterium Chloroflexus aurantiacus, the as yet unknown bacteriochlorophyll cs was isolated in addition to small amounts of the known bacteriochlorophyll ap. The new bacteriochlorophyll cs is the main photosynthetic pigment of these organisms under the growth conditions used. It is different from the known bacteriochlorophylls c, as could be shown unequivocally by chromatographic examinations. Evidence for the structure of the new bacteriochlorophyll cs was obtained from mass spectra. The u.v./vis.-spectra and the chromatographic behavior are in accord with the suggested structure. The result includes two particularly interesting aspects: 1. Unlike the bacteriochlorophylls c, d, and e of the Chlorobiaceae, bacteriochlorophyll cs of Chloroflexus is not a mixture of isomeric and homologous molecules; 2. the esterifying alcohol of the propionic acid side chain is neither farnesol nor another isoprenoid alcohol, but is the straight chain aliphatic (C-18) stearylalcohol.
Asunto(s)
Bacterias/análisis , Bacterioclorofilas/análisis , Clorofila/análogos & derivados , Fenómenos Químicos , Química , Especificidad de la EspecieRESUMEN
A new bacteriochlorophyll has been isolated by thin layer chromatography from all strains of the brown-colored Chlorobiaceae Chlorobium phaeobacteroides and Chlorobium phaeovibriodes. The new bacteriochlorophylle--like the bacteriochlorophylls c and d--represents the major amounts of bacteriochlorophyll a. Bacteriochlorophyll e can be differentiated from the bacteriochlorophylls c and d by its absorption maxima in aceton and its different Rf-value in the thin layer chromatogram. The structure of the new bacteriochlorophyll e has been elucidated on the basis of mass spectra, 1H-and 13C-NMR-spectra, the UV/VIS-spectrum as well as IR-, ORD-, and CD-spectra. The new bacteriochlorophyll has the same relationship to bacteriochlorophyll c as chlorophyll b from green plants to chlorophyll a; therefore, bacteriochlorophyll e represents the first formyl-substituted chlorophyll from bacteria. Similar to the bacteriochlorophylls c and d, the new bacteriochlorophyll e consists of a mixture of at least three homologues which differ from each other by different substituents on the pyrrol rings II and III.