Phosphatidylglycerol and Related Lipids
Phosphatidylglycerol is a lipid present in all kingdoms of life that can be a major component of some bacterial membranes, and while it is often of lower abundance in membranes of plants and animals, it has many vital functions in these too. The charge on the phosphate group means that it is an anionic lipid at neutral pH with a larger head group than might be expected because of hydration and with a cylindrical shape overall. The molecule has two chiral centres with the non-acylated glycerol linked to phosphate via position sn-1' normally (but not always exclusively). The 1‑palmitoyl-2-oleoyl species, a constituent of lung surfactant, is illustrated.
Aside from its importance as a membrane constituent, phosphatidylglycerol is an intermediate in the biosynthesis of other lipids in animals and plants but especially of cardiolipin, which is located in the inner mitochondrial membrane and is required by the enzymes for oxidative phosphorylation. It is the precursor for acylphosphatidylglycerol and the complex lipoamino acids of bacteria.
1. Occurrence and Function of Phosphatidylglycerol in Anaerobic Bacteria
Phosphatidylglycerol is found in almost all bacterial types, representing 20-25% of the phospholipids in most Gram-negative bacteria, i.e., with a double (outer and inner) phospholipid envelope, where it is present only in the inner membrane (there is a schematic diagram in our web page on Lipid A). Escherichia coli, a widely studied 'model' organism, has up to 20% of phosphatidylglycerol in its membranes (phosphatidylethanolamine makes up much of the rest with a little cardiolipin). In Gram-positive bacteria, which have a single phospholipid bilayer coated with peptidoglycans, phosphatidylglycerol can be as high as 60% of the phospholipids (together with glycosyldiacylglycerols). In many bacteria, the diacyl form of the lipid predominates, but in others the alkylacyl and alkenylacyl forms are more abundant.
There is
conflicting evidence as to whether E. coli has an absolute requirement for phosphatidylglycerol in its membranes.
Some studies with mutants deficient in phosphatidylglycerol have suggested that its absence results in defective DNA replication and a lack of
a necessary modification to the main cellular lipoprotein or proteolipid, leading to
membrane welding and eventually cell death, but others have concluded from similar experiments that phosphatidylglycerol and cardiolipin
are dispensable and can be substituted by phosphatidylethanolamine and anionic phospholipids such as phosphatidic acid.
There seems little doubt that phosphatidylglycerol is required for the optimal operation of the bacterial machinery under normal conditions,
and it has a role in protein folding and binding, while activating a glycerol phosphate acyl transferase to suggest that it may be involved
in a positive feedback loop that produces phosphatidic acid and thus all other membrane lipids.
There is evidence that in some bacterial membranes, phosphatidylglycerol may be segregated into distinct domains, which differ in lipid and protein composition and degree of order from other regions. For example, the conjugative E. coli F pilus, a channel necessary for the reproduction of the organism, is assembled from protein-phospholipid units lined with stoichiometrically arranged phosphatidylglycerol molecules in which their head groups are directed to the interior of the pilus and the acyl chains buried entirely between subunits. Incidentally, a study with Bacillus subtilis has shown that the antibiotic daptomycin requires an interaction in the cell wall with phosphatidylglycerol of the normal chiral conformation, i.e., the 2R,2'S stereoisomer.
Two unusual phosphatidylglycerol derivatives based on an archaeol backbone, i.e., phosphatidylglycerol sulfate and phosphatidylglycerol phosphate methyl ester, are unique constituents of the primitive organisms, the Haloarchaea. In these organisms, they are constituents of bacteriorhodopsin, a retinal-containing integral membrane protein of the cytoplasmic membrane, which forms two-dimensional crystalline patches known as the purple membrane. Phosphatidylglycerol is the biosynthetic precursor of many other phospholipids, which may have crucial properties for the bacteria that produce them, including further phosphatidylglycerol analogues, the complex lipoamino acids and acylphosphatidylglycerols (discussed below).
2. Occurrence and Function of Phosphatidylglycerol in Plants and Photosynthetic Bacteria
In the photosynthetic membranes of leaf tissue of higher plants, including the model plant Arabidopsis thaliana, phosphatidylglycerol is in essence the only phospholipid and is unique in that in contains a high proportion of trans‑3‑hexadecenoic acid, which is located exclusively in position sn-2 (Table 1). This fatty acid is not found in other lipids of the thylakoid membrane, and it must be significant that the rate of its synthesis in leaves deprived of light is greatly reduced (with accumulation of the precursor palmitic acid); it increases in concentration by a factor of 20 between the youngest (basal) and oldest (distal) leaf sections. In studies with Arabidopsis mutants, it has been demonstrated that phosphatidylglycerol biosynthesis is necessary for the development of embryos and the normal membrane structures of chloroplasts and mitochondria.
Table 1. Composition (mol %) of fatty acids in positions sn-1 and sn-2 of phosphatidylglycerol from leaves of Arabidopsis thaliana and from Synechocystis sp. |
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| Position | Fatty acids | |||||
|---|---|---|---|---|---|---|
| 16:0 | trans-3-16:1 | 18:0 | 18:1 | 18:2 | 18:3(n-3) | |
| Arabidopsis thaliana [1] | ||||||
| sn-1 | 22 | - | trace | 9 | 13 | 55 |
| sn-2 | 43 | 41 | trace | 1 | 8 | 8 |
| Synechocystis sp. [2] | ||||||
| sn-1 | 18 | 2 | 6 | 10 | 58 | |
| sn-2 | 92 | 2 | 2 | trace | - | |
| [1] Browse, J. et al. Biochem. J., 235, 25-31 (1986);
DOI. [22] Wada, H. and Murata, N. Plant Physiol., 92, 1062–1069 (1990); DOI. |
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It is interesting to note that saturated and monoenoic fatty acids are concentrated in position sn-2 and polyunsaturated in position sn-1, the opposite of that found for most animal phospholipids. This is because phosphatidylglycerol is synthesised in chloroplasts via the so-called "prokaryotic" pathway (now known to be a misnomer - see our web-pages on mono- and digalactosyldiacylglycerols for further discussion of this mechanism). In some plant species, position sn-2 of the thylakoid phosphatidylglycerol is occupied exclusively with C16 fatty acids giving a rather distinctive molecular species distribution.
In cyanobacteria and plants that can carry out aerobic photosynthesis, phosphatidylglycerol is found in all cellular membranes (2 to 5% of the plasma membrane) but especially in the thylakoid membrane, which surrounds the chloroplast. There, it is the only phospholipid, comprising up to 10% of the total lipids with a high proportion (up to 70%) in the outer monolayer (much of the remaining lipid is digalactosyldiacylglycerols). In Synechocystis sp., position sn-1 of phosphatidylglycerol is occupied mainly by oleate and linoleate, while position sn-2 contains palmitate, a structure that is crucial for growth and photosynthesis in this species (the relevant compositions for the galactosyldiacylglycerols of this species are listed are listed here..)
Phosphatidylglycerol
is essential for the oligomerization of photosystems I and II in cyanobacteria.
Analysis of the crystal structure of the photosystem I of cyanobacteria (Thermosynechococcus elongatus) has shown that it contains three
molecules of phosphatidylglycerol and one of monogalactosyldiacylglycerol
as integral components, while in the PSII of T. vulcanus, all five phosphatidylglycerol molecules are deeply buried near
the reaction centre.
It binds to a specific polypeptide component of the photosystem II complex and appears to take part in electron transport.
This phospholipid is also required for crystallization and polymerization of the light-harvesting complex II in pea
chloroplasts, where it may be the 'glue' that binds the individual protein components.
When phosphate is limiting in plants, the glycolipid sulfoquinovosyldiacylglycerol
accumulates to compensate for decreased phosphatidylglycerol levels, but this compensation does not apply to photosynthetic electron transport.
Indeed, Arabidopsis mutants lacking phosphatidylglycerol synthases are unable to produce thylakoid membranes (and viable seeds).
A report that trans-3-hexadecenoic acid in phosphatidylglycerol is necessary for photosynthesis does not hold in Arabidopsis but may be true for Chlamydomonas reinhardtii as PSII activity was abolished in mutants lacking this fatty acid, although phosphatidylglycerol levels were also reduced in the latter so might explain the phenomenon. 3t-16:1-Phosphatidylglycerol may be needed to stimulate the thylakoid membrane-associated phospholipase PLIP1, which is required for biosynthesis of seed oil.
Disaturated molecular species of phosphatidylglycerol in plants are believed to be factors in sensitivity to chilling, and experiments with genetic modifications to increase the degree of unsaturation of this lipid have produced plants with a greater resistance to cold. As there are discrepancies between the results of different experimental approaches, other factors are certainly involved. Phosphatidylglycerol is a factor in the temperature responsiveness of flowering; a mobile protein, known as florigen, moves through the phloem over long distances to reach the shoot apical meristem, where it induces flowering by regulating nuclear transcription. In cold weather, this protein is sequestered by phosphatidylglycerol, so flowering is delayed; warming has the opposite effect by reducing the bonding and allowing the protein to move.
In addition to its role in photosynthesis in cyanobacteria such as Synechocystis sp., phosphatidylglycerol is intimately involved in the regulation of enzymes for respiration, metabolism, transport, transcription and translation (ca. 80 proteins). Here, its propensity to form non-bilayer structures in the presence of calcium ions may be significant, aided by its ability to bind to certain proteins. There may be parallels in plastids of higher plants.
3. Occurrence and Function of Phosphatidylglycerol in Animal Tissues
Phosphatidylglycerol is present at a level of 1-2% in most animal tissues, but it can be the second most abundant phospholipid in lung surfactant at up to 11% of the total in the alveolar hypophase (in a few species, including the rhesus monkey, it is replaced by another acidic lipid, phosphatidylinositol). It is well established that the concentration of phosphatidylglycerol increases during foetal development, coincident with the formation of stable lamellar phases. The fatty acid composition of lung tissue from several species is listed in Table 2.
Table 2. Fatty acid composition (weight % of the total) in lung phosphatidylglycerol from various species. |
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| Fatty acid | Species | |||
|---|---|---|---|---|
| pig | cow | rabbit | guinea pig | |
| 16:0 | 27 | 34 | 29 | 37 |
| 16:1 | 2 | 1 | 3 | 6 |
| 18:0 | 21 | 15 | 19 | 18 |
| 18:1 | 34 | 37 | 27 | 24 |
| 18:2 | 7 | 3 | 8 | 5 |
| 18:3 | 1 | 2 | 1 | 2 |
| 20:3 | 1 | 1 | 1 | trace |
| 20:4(n-6) | 3 | 3 | 4 | 3 |
| 22:4(n-6) | 1 | 1 | 3 | 2 |
| 22:5(n-3) | 1 | 1 | 3 | 1 |
| 22:6(n-3) | 1 | 1 | 1 | 1 |
| Data from: Okano, G. and Akino, T. Lipids, 14, 541-546 (1979); DOI. | ||||
With each species, the content of saturated fatty acids is high while that of the polyunsaturated components is relatively low in comparison to phospholipids in other tissues. Lung phosphatidylglycerol in many animals contains a high proportion of disaturated molecular species, although this does not appear to be true of human lung surfactant, where palmitoyl-oleoyl phosphatidylglycerol is the main molecular species. The complex nature of how phosphatidylglycerol and this single molecular species function in humans is only slowly being revealed, but it may aid the spreading of dipalmitoyl-phosphatidylcholine, which is presumed to be the main effective component of lung surfactant, i.e., a lipid and protein complex (90% phospholipids and 10% protein, by weight), which regulates the biophysics of the alveoli to prevent lung collapse. On the other hand, it is possible that the acidic head-group is more important to phosphatidylglycerol as a surfactant than the precise molecular species composition.
Together with phosphatidylinositol, it has a role in the regulation of the innate immune response in the lungs in part by attenuating inflammation induced by bacterial lipopolysaccharides and in part by blocking certain viral infections. With the former, it antagonizes the cognate ligand activation of the toll-like receptors (TLR2/1, TLR3, TLR4, and TLR2/6) by interacting with subsets of multiprotein receptor components, while it disrupts the binding of virus particles to the plasma membrane receptors required for viral uptake in host cells, including influenza and SARS-CoV-2 viruses. In addition, it suppresses pathogen-induced eicosanoid production resulting from Mycoplasma pneumoniae infection in macrophages, as the alveolar surfactant protein A binds strongly to the phosphatidylglycerol in the surface membranes of this organism to attenuate its activity. It can be used in a clinical treatment for respiratory distress syndrome because it prevents alveolar epithelial apoptosis and blocks the inflammatory agents that cause acute lung injury.
As an example of another tissue, the positional distribution of fatty acids in rat liver phosphatidylglycerol is listed in Table 3. Like cardiolipin for which it is the biosynthetic precursor, there is a very high proportion of linoleate, much of which is concentrated in position sn-1, with relatively little polyunsaturates.
Table 3. Positional distribution of fatty acids in phosphatidylglycerol from rat liver. |
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| Position | Fatty acid | |||||
|---|---|---|---|---|---|---|
| 16:0 | 18:0 | 18:1 | 18:2 | 20:4 | 22:6 | |
| sn-1 | 7 | 3 | 3 | 81 | ||
| sn-2 | 3 | 1 | 34 | 50 | 2 | 1 |
| Data from: Wood, R. and Harlow, R.D. Arch. Biochem. Biophys., 135, 272-281 (1969); DOI. | ||||||
In mammalian cells, phosphatidylglycerol is known to bind non-covalently to various membrane transporter and channel proteins, and it stimulates a nuclear protein kinase C while inhibiting some of the effects of platelet-activating factor. The enzyme cytochrome c oxidase, the last enzyme in the respiratory electron transport chain of mitochondria, contains four molecules of phosphatidylglycerol in its crystal structure.
Phosphatidylglycerol from bacteria such as Mycobacterium tuberculosis and Listeria monocytogenes interacts with the CD1 family of antigen-presenting molecules in Type II Natural Killer T (NKT) cells in mammalian hosts, suggesting a role in protective immunity towards these pathogens. Presumably, the mammalian cells can recognize the changes in structure and physical properties arising from the very different fatty acid compositions (saturated and branched chain) of the bacterial lipids.
4. Biosynthesis of Phosphatidylglycerol
In animal, plant and microbial tissues, phosphatidylglycerol is formed from phosphatidic acid by a sequence of enzymatic reactions that proceeds via the intermediate, cytidine diphosphate diacylglycerol (CDP-diacylglycerol), which is rarely detected as a normal component of tissues amounting to only 0.05% or so of the total phospholipids. Biosynthesis starts with the condensation of phosphatidic acid and cytidine triphosphate with elimination of pyrophosphate via the action of phosphatidate cytidyltransferases or CDP-synthases, mainly AMM41/TAM41 in animals and yeast but six forms in Arabidopsis, and believed to be rate-limiting - step 1 in the figure. The same liponucleotide is the key intermediate in the biosynthesis of phosphatidylinositol, but different routes are taken to phosphatidylcholine and phosphatidylethanolamine.
In Step 2, the first committed step in phosphatidylglycerol synthesis, CDP-diacylglycerol reacts with glycerol-3-phosphate via the enzyme phosphatidylglycerophosphate synthase (PGPS) to form 3-sn-phosphatidyl-1'-sn-glycerol 3'-phosphoric acid, with the release of cytidine monophosphate (CMP). One enzyme (PgsA) is found in E. coli in the mitochondria, but two such enzymes are present in the chloroplasts of eukaryotes such as Arabidopsis. With the latter PGPS1 is targeted to both mitochondria and chloroplasts, whereas PGPS2 is present only in the endoplasmic reticulum and makes a relatively minor contribution to phosphatidylglycerol synthesis. In animal tissues, biosynthesis occurs in the endoplasmic reticulum and in mitochondria. Finally, phosphatidylglycerol is formed by the action of one of two phosphatases in animals - step 3, but the Arabidopsis PGPP1 protein is located mainly in the chloroplast and is crucial for plastidial phosphatidylglycerol synthesis. As biosynthesis is via glycerol-3-phosphate, the second glycerol moiety is attached to the phosphate group via position sn-1'. In cyanobacteria, steps 1, 2 and 3 are carried out by enzymes designated CdsA, PgsA and Pgpp, respectively.
There are other minor biosynthetic routes to phosphatidylglycerol, e.g., by phospholipase D-catalysed catabolism of cardiolipin or by glycerolysis of other phospholipids (also catalysed by phospholipase D), which can change the stereochemistry of the second glycerol moiety in part (in effect, racemization). In some bacteria, including E. coli, the cardiolipin synthase ClsB acts in this way to catalyse headgroup exchange between phosphatidylethanolamine and glycerol to form small amounts of phosphatidylglycerol and free ethanolamine.
The eventual fatty acid composition of phosphatidylglycerol in animal tissues is attained in the endoplasmic reticulum by a process of remodelling known as the Lands' cycle (see the web page on phosphatidylcholine for a more extensive discussion). The first step, is hydrolysis by a phospholipase A2 to lysophosphatidylglycerol, followed by reacylation by means of an acyl-CoA:lysophosphatidylglycerol acyltransferase. The human form of the latter, designated LPLAT1 (LPGAT1), has been characterized and was found to prefer 16:0-, 18:0- and 18:1-CoA esters as donors. Defective remodelling by this enzyme is believed to be the cause of the genetic disorder MEGDEL syndrome.
In the plastids of higher plants, the selectivity of the acyltransferases is such that the initial molecular species formed contains oleic acid in position sn-1 and palmitic acid in position sn-2. Some of the palmitate in position sn-2 is desaturated to the trans-3 isomer by FAD4, while the oleate in position sn-1 is desaturated to 18:2 and 18:3 fatty acids (see our web page on polyunsaturated fatty acids). In the endoplasmic reticulum in contrast, the initial molecular species contain palmitic and oleic acids in position sn-1 and oleic acid in position sn-2, and the oleate, but not palmitate, is further desaturated by acyl-lipid desaturases until the final fatty acid compositions are attained. The biosynthetic processes that occur in mitochondria have still to be determined in detail. In cyanobacteria, a disaturated molecular species of phosphatidylglycerol is synthesised first, and the fatty acid in position sn-1 is subsequently desaturated by acyl-lipid desaturases; that in position sn-2 is not affected.
As discussed in other web pages of this site, much of the phosphatidylglycerol formed is utilized for the biosynthesis of cardiolipin, and it is the precursor for bis(monoacylglycero)phosphate and many glycophospholipids, as well as bacterial proteolipids, lipoteichoic acids and the complex lipoamino acids (the last are discussed below).
Lysophosphatidylglycerol, with a fatty acid in position sn-1 only, has been reported to have some biological properties in animal tissues in vitro, but it is not known whether all of these are relevant in vivo. Elevated concentrations have been detected in acute coronary syndrome and these may be linked to the pathogenesis of cardiovascular diseases. Similarly, it may be a biomarker for eosinophilic asthma and lung fibrosis. Bacterial capsular lipopolysaccharides, which are virulence factors for many pathogens, contain it as the conserved terminal element. In Staphylococcus aureus, a phospholipase D converts lysophosphatidylglycerol to lysophosphatidic acid, which is re-cycled into the phosphatidylglycerol biosynthetic pathway.
5. Acylphosphatidylglycerol
Acylphosphatidylglycerol or
(1,2-diacyl-sn-glycero-3-phospho-(3'-acyl)-1'-sn-glycerol) was first isolated as a minor component of the phospholipids
of the bacterium Salmonella typhimurium, and it has since been found in many prokaryotic species, including E. coli.
It is a characteristic lipid in the membranes of Corynebacteria and is abundant in those species that lack mycolic acids.
C. amycolatum, for example, contains 20 to 29% of this lipid, with mainly C14 to C18 saturated and monoenoic
fatty acid components; the fatty acid on the head group glycerol is mainly oleate.
It has been found in parasitic protozoa, such as Trichomonas vaginalis and T. foetus.
In plants, it is present in oats (Avena sativa), where it may be relevant that this species is known to contain
N‑acylphosphatidylethanolamine in appreciable amounts, and acylphosphatidylglycerol with one of the fatty acids
an oxylipin has been detected in stressed A. thaliana.
Acylphosphatidylglycerol is formed in vitro in experiments designed to study the biosynthesis of bis(monoacylglycero)phosphate (lysobisphosphatidic acid) in animal cells, and in this instance the fatty acid on the glycerol head group is presumed to be in the sn-2' position. It is not clear whether it occurs naturally in animal tissues in vivo.
Bis-phosphatidic acid or phosphatidyldiacylglycerol (fully acylated phosphatidylglycerol) is occasional reported from bacteria and it can be produced as a minor component of animal cells by trans-phosphatidylation of phosphatidylcholine with diacylglycerol, catalysed by the enzyme phospholipase D, a possible mechanism for removing excess messenger diacylglycerol. In this instance, the stereochemistry of the second glycerol is presumably different from that in normal phosphatidylglycerol, i.e., the phosphate will be attached to the sn-3/sn-3' positions. The bis-phosphatidic acid found in lysosomes is related to bis(monoacylglycero)phosphate.
6. Complex Lipoamino Acids
In some species of Gram-positive bacteria or rarely in certain Gram-negative bacteria, the 3'-hydroxyl of the phosphatidylglycerol moiety may be esterified to an amino acid (lysine, ornithine, alanine, or less commonly arginine or glycine) to form an O‑aminoacylphosphatidylglycerol. Such lipids been termed lipoamino acids, though it might be better to call them "complex lipoamino acids" to distinguish them from those consisting simply of a fatty acids linked to an amino acid, such as the ornithine lipids, which are presumed to have similar functions. There are related complex lipoamino acids derived from cardiolipin in some bacterial species.
Lysyl-phosphatidylglycerol (lysyl-PG) is a major membrane lipid (20 to 40%) in Staphylococcus aureus, while ornithyl-PG is present in Mycobacterium tuberculosis and alanyl-PG in Clostridium perfringens. An N-succinylated L-lysylphosphatidylglycerol has been detected in B. subtilis that interestingly reverses the net positive charge of lysyl-PG. Enterococcus faecalis has been reported to contain alanyl-PG, 2'-lysyl-PG, 3'-lysyl-PG, 2',3'-dilysyl-PG and arginyl-PG (together with a diglucosyl derivative of PG), and alkylacyl- and alkenylacyl-forms have been detected in addition to diacyl lipids. It should be noted that 2'‑lysyl-PG can undergo acyl migration to yield 3'-lysyl-PG. Related lipids containing glycine, ornithine, L- and D-threonine, and L- and D-allo-threonine have been found in other bacterial species.
An enzyme MprF ("multiple peptide resistance factor") is one of a highly conserved family of aminoacyl phosphatidylglycerol synthases in bacteria that can transfer lysine or alanine from the appropriate aminoacyl-tRNAs (the same substrates as for protein biosynthesis) to the 3'‑hydroxyl group of phosphatidylglycerol (or cardiolipin) to form lysyl- or alanyl-phosphatidylglycerol, respectively. In Staphylococcus aureus, the C-terminal domain of MprF is sufficient for the full production of lysylphosphatidylglycerol at the inner leaflet of the cytoplasmic membrane, whereas the N-terminal MprF domain translocates the newly formed lipid from the inner to the outer leaflet and therefore acts as a floppase (and is considered to be a target for the development of new antibiotics). Related enzymes are present in many other bacterial species, some of which can only utilize a single lipoamino acid while others can produce several products, but nothing comparable has been identified in eukaryotic genomes.
In comparison to the precursor phosphatidylglycerol and cardiolipin, which have negatively charged head groups, the aminoacylated products are cationic or zwitterionic. It is now evident that these complex lipoamino acids in the membranes of bacteria lower the net negative charge of their cellular envelope to protect them from antimicrobial cationic polypeptides produced by other bacteria (bacteriocins), plants and animals, and perhaps facilitate the interaction of pathogenic bacteria with their host. They are believed to protect against environmental stresses such as those encountered during extreme osmotic or acidic conditions, as membranes containing these lipids are much less permeable than those containing phosphatidylglycerol per se.
Although they are not related to phosphatidylglycerol, the betaine lipids, phosphatidylserine, phosphatidylthreonine, lysyl-diacylglycerol and related lipids discussed elsewhere on this site for various practical reasons are sometimes termed complex lipoamino acids.
7. Analysis
Phosphatidylglycerol is not the easiest phospholipid to analyse, as it tends to elute close to phosphatidic acid in many chromatographic systems, although it can usually be resolved by two-dimensional thin-layer chromatography. Electrospray mass spectrometry under negative ionization conditions appears to be well suited to determination of molecular species compositions and to the analysis of the complex lipoamino acids.
Recommended Reading
- Agassandian, M. and Mallampalli, R.K. Surfactant phospholipid metabolism. Biochim. Biophys. Acta, Lipids, 1831, 612-625 (2013); DOI.
- Boudière, L. and others. Glycerolipids in photosynthesis: Composition, synthesis and trafficking. Biochim. Biophys. Acta, Bioenergetics, 1837, 470-480 (2014); DOI.
- Christie, W.W. and Han, X. Lipid Analysis - Isolation, Separation, Identification and Lipidomic Analysis (4th edition), 446 pages (Oily Press, Woodhead Publishing and now Elsevier) (2010) - see Science Direct.
- Dowhan, W. and Bogdanov, M. Eugene P. Kennedy's legacy: defining bacterial phospholipid pathways and function. Front. Mol. Biosci., 8, 666203 (2021); DOI.
- Dugail, I., Kayser, B.D. and Lhomme, M. Specific roles of phosphatidylglycerols in hosts and microbes. Biochimie, 141, 47-53 (2017); DOI.
- Furse, S. Is phosphatidylglycerol essential for terrestrial life? J. Chem. Biol., 10, 1-9 (2017); DOI.
- Hsu, F.F., Turk, J., Shi, Y.X. and Groisman, E.A. Characterization of acylphosphatidylglycerols from Salmonella typhimurium by tandem mass spectrometry with electrospray ionization. J. Am. Soc. Mass Spectrom., 15, 1-11 (2004); DOI.
- Kimura, T., Jennings, W. and Epand, R.M. Roles of specific lipid species in the cell and their molecular mechanism. Prog. Lipid Res., 62, 75-92 (2016); DOI.
- Kobayashi, K., Jimbo, H., Nakamura, Y. and Wada, H.Biosynthesis of phosphatidylglycerol in photosynthetic organisms. Prog. Lipid Res., 93, 101266 (2024); DOI.
- López-Lara, I.M. and Geiger, O. Bacterial lipid diversity. Biochim. Biophys. Acta., 162, 203-224 (2017); DOI.
- Numata, M., Kandasamy, P. and Voelker, D.R. The anti-inflammatory and antiviral properties of anionic pulmonary surfactant phospholipids. Immun. Rev., 317, 166-186 (2023); DOI.
- Ren, M., Phoon, C.K.L. and Schlame, M. Metabolism and function of mitochondrial cardiolipin. Prog. Lipid Res., 55, 1-16 (2014); DOI.
- Slavetinsky, C., Kuhn, S. and Peschel, A. Bacterial aminoacyl phospholipids – Biosynthesis and role in basic cellular processes and pathogenicity. Biochim. Biophys. Acta, Lipids, 1862, 1310-1318 (2017); DOI.
- Yeagle, P.L. Non-covalent binding of membrane lipids to membrane proteins. Biochim. Biophys. Acta, Biomembranes, 1838, 1548-1559 (2014); DOI.
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© Author: William W. Christie |  |
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