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

The cell membranes of many archaea contain characteristic membrane-spanning lipids known as glycerol dibiphytanyl glycerol tetraethers. Here, Zeng et al. identify a protein that participates in a key step of the synthesis of these lipids from diether precursors. 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.

Automated summary

This study identified a protein involved in the synthesis of characteristic membrane lipids in archaea, which plays a crucial role and provides a competitive advantage in extreme environments.