%0 Journal Article %A Jahnke, Linda L. %A Stan-Lotter, Helga %A Kato, Katharine %A Hochstein, Lawrence I. %T Presence of methyl sterol and bacteriohopanepolyol in an outer-membrane preparation from Methylococcus capsulatus (Bath) %D 1992 %J Microbiology, %V 138 %N 8 %P 1759-1766 %@ 1465-2080 %R https://doi.org/10.1099/00221287-138-8-1759 %I Microbiology Society, %X Cytoplasmic/intracytoplasmic and outer membrane preparations of Methylococcus capsulatus (Bath) were isolated by sucrose density gradient centrifugation of a total membrane fraction prepared by disruption using a French pressure cell. The cytoplasmic and/or intracytoplasmic membrane fraction consisted of two distinct bands, Ia and Ib (buoyant densities 1.16 and 1.18 g ml−1, respectively) that together contained 57% of the protein, 68% of the phospholipid, 73% of the ubiquinone and 89% of the CN-sensitive NADH oxidase activity. The only apparent difference between these two cytoplasmic bands was a much higher phospholipid content for Ia. The outer membrane fraction (buoyant density 1.23–1.24 g ml−1) contained 60% of the lipopolysaccharide-associated, β-hydroxypalmitic acid, 74% of the methylsterol, and 66% of the bacteriohopanepolyol (BHP); phospholipid to methyl sterol or BHP ratios were 6:1. Methanol dehydrogenase activity and a c-type cytochrome were also present in this outer membrane fraction. Phospholipase A activity was present in both the cytoplasmic membrane and outer membrane fractions. The unique distribution of cyclic triterpenes may reflect a specific role in conferring outer membrane stability in this methanotrophic bacterium. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-138-8-1759