Quinones of phototrophic purple bacteria

The quinone composition of the recognized species of the phototrophic purple nonsulfur bacteria, the Ectothiorhodospiraceae, and some Chromatiaceae species has been determined. Altogether more than 50 strains of 33 species have been investigated. Some of the purple nonsulfur bacteria have Q-10 as sole quinone component, while others have Q-10, Q-9, or Q-8, respectively, together with menaquinones of the same isoprenoid chain length as the major components. Rhodoquinone is present in Rhodospirillum rubrum and Rhodospirillum photometricum. The Ectothiorhodospira species have either Q-8 and MK-8, like the Chromatiaceae species, or Q-7 and MK-7 as the major components.