The biosynthesis of the saturated isoprenoid portion of membrane lipids of the halophilic archaea Natrinema pallidum was investigated. At first, a practical method for the synthesis of [3-(2H3)methyl]mevalonate was developed. Then, incorporation experiments of [3-(2H3)methyl]mevalonate into the lipid core indicated that the isoprenoid portion was derived from mevalonate. However, a [2-13C]acetate-incorporation experiment revealed a significant difference in the degree of 13C enrichment between the expected position from the mevalonate pathway, the CH2 groups (and at one terminal CH3 group) and the CH3 groups in the saturated isoprenoid chain. These results suggest that (1) the mevalonate pathway exists and is active, and (2) a part of acetoacetyl-CoA is not derived from an acetate in the biosynthesis of the isoprenoidal lipid-core of the archaebacterium.
All Science Journal Classification (ASJC) codes