Publications

• Identification of a protein responsible for the synthesis of archaeal membrane-spanning GDGT lipids.

  Zeng Z., Chen H., Yang H., Chen Y., Yang W., Feng X., Pei H., Welander P.V.

  Glycerol dibiphytanyl glycerol tetraethers (GDGTs) are archaeal monolayer membrane lipids that can provide a competitive advantage in extreme environments. Here, we identify a radical SAM protein, tetraether synthase (Tes), that participates in the synthesis of GDGTs. Attempts to generate a tes-de ... >> More

  Glycerol dibiphytanyl glycerol tetraethers (GDGTs) are archaeal monolayer membrane lipids that can provide a competitive advantage in extreme environments. Here, we identify a radical SAM protein, tetraether synthase (Tes), that participates in the synthesis of GDGTs. Attempts to generate a tes-deleted mutant in Sulfolobus acidocaldarius were unsuccessful, suggesting that the gene is essential in this organism. Heterologous expression of tes homologues leads to production of GDGT and structurally related lipids in the methanogen Methanococcus maripaludis (which otherwise does not synthesize GDGTs and lacks a tes homolog, but produces a putative GDGT precursor, archaeol). Tes homologues are encoded in the genomes of many archaea, as well as in some bacteria, in which they might be involved in the synthesis of bacterial branched glycerol dialkyl glycerol tetraethers. << Less

  Nat Commun 13:1545-1545(2022) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Discovery, structure and mechanism of a tetraether lipid synthase.

  Lloyd C.T., Iwig D.F., Wang B., Cossu M., Metcalf W.W., Boal A.K., Booker S.J.

  Archaea synthesize isoprenoid-based ether-linked membrane lipids, which enable them to withstand extreme environmental conditions, such as high temperatures, high salinity, and low or high pH values^1-5. In some archaea, such as Methanocaldococcus jannaschii, these lipids are further mod ... >> More

  Archaea synthesize isoprenoid-based ether-linked membrane lipids, which enable them to withstand extreme environmental conditions, such as high temperatures, high salinity, and low or high pH values^1-5. In some archaea, such as Methanocaldococcus jannaschii, these lipids are further modified by forming carbon-carbon bonds between the termini of two lipid tails within one glycerophospholipid to generate the macrocyclic archaeol or forming two carbon-carbon bonds between the termini of two lipid tails from two glycerophospholipids to generate the macrocycle glycerol dibiphytanyl glycerol tetraether (GDGT)^1,2. GDGT contains two 40-carbon lipid chains (biphytanyl chains) that span both leaflets of the membrane, providing enhanced stability to extreme conditions. How these specialized lipids are formed has puzzled scientists for decades. The reaction necessitates the coupling of two completely inert sp³-hybridized carbon centres, which, to our knowledge, has not been observed in nature. Here we show that the gene product of mj0619 from M. jannaschii, which encodes a radical S-adenosylmethionine enzyme, is responsible for biphytanyl chain formation during synthesis of both the macrocyclic archaeol and GDGT membrane lipids⁶. Structures of the enzyme show the presence of four metallocofactors: three [Fe₄S₄] clusters and one mononuclear rubredoxin-like iron ion. In vitro mechanistic studies show that Csp³-Csp³ bond formation takes place on fully saturated archaeal lipid substrates and involves an intermediate bond between the substrate carbon and a sulfur of one of the [Fe₄S₄] clusters. Our results not only establish the biosynthetic route for tetraether formation but also improve the use of GDGT in GDGT-based paleoclimatology indices^7-10. << Less

  Nature 609:197-203(2022) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.