Occurrence of menaquinones and some novel methylated menaquinones in the alkaliphilic, extremely halophilic archaebacterium Natronobacterium gregoryi

The respiratory quinone composition of the alkaliphilic, extremely halophilic archaebacterium Natronobacterium gregoryi was investigated. The two major respiratory quinones corresponded to unsaturated and VIII-dihydrogenated menaquinones with 8 isoprene units [MK-8, MK-8(VIII-H2)]. Four hitherto unknown methylated menaquinone prenologues were also present as minor components. Mass spectral (MS) and 1H nuclear magnetic resonance (NMR) analyses demonstrated these minor quinones corresponded to unsaturated and VIII-dihydrogenated monomethylmenaquinones [MMK-8, MMK-8(VIII-H2) and dimethylmenaquinones (DMMK-8, DMMK-8(VIII-H2)].