[BBG02-P03] The precise structure of “unsaturated” archaeol derivatives in the halophilic archaea lipid-core
Keywords:halophilic archaea, archaeologists, ether lipid
Archaea has a characteristic lipid-core, archaeol. Further, a characteristic diether lipid-core (C20-C25diether (1)) which is constructed from one C25 and one C20isoprenoid is produced by halophilic archaea[1]. Recently, Dawson et al. showed the existence of several unsaturated isoprenoid diethers (such as tentative structure 2) in the lipid-core of several halophilic archaea which was incubated with very high salt concentration[2].
Then, 2, and the regioisomeric structure about the double bond and ether bond with a glycerol, 3to 5were chemically synthesized according to the reported method and the comparison of the mass spectrum of trimethylsilyl (TMS) ether were presented previously at this meeting[3].Further, 3 or 4may be a possible structure of the real compound Dawson et al. shown at the mass spectrum.
About these unsymmetrical diether. The halophilic archaea Haloferax sulfrifonis was incubated and the lipid core was extracted and isolated.The analysis of the lipic core was perforemd by the GC-MS of the TMS ether. At first, 1 was detected as a main core lipid compornent. And the compound almost identical the mass specrum with the synthetic structure 2 was detected with a second minor compornent. Careful analysis of the compornent, the srtucture almost identical with 4 is also detected. This result showed the double bond in the unsaturated archaeol in H. sulfrifonisis the mixture of 2 and 4. Dawson's unsaturated diether does not have a double bond at the methyl group branching position resulting from the usual isoprenoid biosynthesis (e.g. phytol), probably unsaturation is formed after the saturated isoprenoid formation with a unspecific fasion. The result of the analysis of lipid core of the archaea having unsaturated C20-C25diether will be presented.
[1]De Rosa et al., J. Gen. Microbiol., 128, 343 (1982).
[2] Dawson et al. Org. Geochem., 48, 1 (2012).
[3] Yamauchi (2018) JpGU meeting 2018 BBG03-P08.
Then, 2, and the regioisomeric structure about the double bond and ether bond with a glycerol, 3to 5were chemically synthesized according to the reported method and the comparison of the mass spectrum of trimethylsilyl (TMS) ether were presented previously at this meeting[3].Further, 3 or 4may be a possible structure of the real compound Dawson et al. shown at the mass spectrum.
About these unsymmetrical diether. The halophilic archaea Haloferax sulfrifonis was incubated and the lipid core was extracted and isolated.The analysis of the lipic core was perforemd by the GC-MS of the TMS ether. At first, 1 was detected as a main core lipid compornent. And the compound almost identical the mass specrum with the synthetic structure 2 was detected with a second minor compornent. Careful analysis of the compornent, the srtucture almost identical with 4 is also detected. This result showed the double bond in the unsaturated archaeol in H. sulfrifonisis the mixture of 2 and 4. Dawson's unsaturated diether does not have a double bond at the methyl group branching position resulting from the usual isoprenoid biosynthesis (e.g. phytol), probably unsaturation is formed after the saturated isoprenoid formation with a unspecific fasion. The result of the analysis of lipid core of the archaea having unsaturated C20-C25diether will be presented.
[1]De Rosa et al., J. Gen. Microbiol., 128, 343 (1982).
[2] Dawson et al. Org. Geochem., 48, 1 (2012).
[3] Yamauchi (2018) JpGU meeting 2018 BBG03-P08.