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1.D.218. The Intrinsic Permeability of Lipid Membranes (IPLM) Family

Comparing the permeability of 18 metabolites in unilamellar vesicles demonstrated that diether glycerol-1-phosphate lipids with methyl branches, often the most abundant membrane lipids of sampled archaea, are permeable to a wide range of compounds useful for core metabolic networks, including amino acids, sugars, and nucleobases. Permeability was significantly lower in diester glycerol-3-phosphate lipids without methyl branches, the common building blocks of bacterial membranes (Łapińska et al. 2023).  Lipid osmosis, membrane tension, and other mechanochemical driving forces of lipid flow have been described (Zhang and Lin 2024).

Comparing the permeability of 18 metabolites demonstrated that diether glycerol-1-phosphate lipids with methyl branches, often the most abundant membrane lipids of sampled archaea, are permeable to a wide range of compounds useful for core metabolic networks, including amino acids, sugars, and nucleobases. Permeability is significantly lower in diester glycerol-3-phosphate lipids without methyl branches, the common building block of bacterial membranes (Łapińska et al. 2023). To identify the membrane characteristics that determine permeability, a variety of lipid forms bearing a diversity of intermediate characteristics were used. Increased membrane permeability was dependent on both the methyl branches on the lipid tails and the ether bond between the tails and the head group, both of which are present in the archaeal phospholipids. These permeability differences must have had profound effects on the cell physiology and proteome evolution of early prokaryotic forms. The abundance and distribution of transmembrane transporter-encoding protein families encoded on genomes sampled from across the prokaryotic tree of life showed that archaea tend to have a reduced repertoire of transporter gene families, consistent with increased membrane permeation (Łapińska et al. 2023).

References associated with 1.D.218 family:

Yu, X.H., C.C. Peng, X.X. Sun, and W.H. Chen. (2018). Synthesis, anionophoric activity and apoptosis-inducing bioactivity of benzimidazolyl-based transmembrane anion transporters. Eur J Med Chem 152: 115-125. 29702447
Zhang, Y. and C. Lin. (2024). Lipid osmosis, membrane tension, and other mechanochemical driving forces of lipid flow. bioRxiv. 38260424
Łapińska, U., G. Glover, Z. Kahveci, N.A.T. Irwin, D.S. Milner, M. Tourte, S.V. Albers, A.E. Santoro, T.A. Richards, and S. Pagliara. (2023). Systematic comparison of unilamellar vesicles reveals that archaeal core lipid membranes are more permeable than bacterial membranes. PLoS Biol 21: e3002048. 37014915