Phospholipid head groups as sensors of electric charge in membranes

Seelig, Joachim; Macdonald, Peter M.; Scherer, Peter G.

doi:10.1021/bi00398a001

Cited by 415 publications

(422 citation statements)

References 61 publications

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“…The G-3-P backbone of phospholipids have a perpendicular orientation at the bilayer interface, followed by a tilted head group further out (37,38). Potent activator lipids of the DGlcDAG synthase all have this part; positively charged moieties covalently linked outside the phosphate (like in PC) prevent activation, whereas a zwitterion (like in PS) works, and no or negative charges (like in PG, DPG, and PI derivatives) (cf.…”

Section: Discussionmentioning

confidence: 99%

The Nonbilayer/Bilayer Lipid Balance in Membranes

Vikström

Wieslander

2000

Journal of Biological Chemistry

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In membranes of Acholeplasma laidlawii a single glucosyltransferase step between the major, nonbilayerprone monoglucosyl-diacylglycerol (MGlcDAG) and the bilayer-forming diglucosyl-diacylglycerol (DGlcDAG) is important for maintenance of lipid phase equilibria and curvature packing stress. This DGlcDAG synthase is activated in a cooperative fashion by phosphatidylglycerol (PG), but in vivo PG amounts are not enough for efficient DGlcDAG synthesis. In vitro, phospholipids with an sn-glycero-3-phosphate backbone, and no positive head group charge, functioned as activators. Different metabolic, soluble phosphates could supplement PG for activation, depending on type, amount, and valency. Especially efficient were the glycolytic intermediates fructose 1,6-bisphosphate and ATP, active at cellular concentrations on the DGlcDAG but not on the preceding MGlcDAG synthase. Potencies of different phosphatidylinositol (foreign lipid) derivatives differed with numbers and positions of their phosphate moieties. A selective stimulation of the DGlcDAG, but not the MGlcDAG synthase, by minor amounts of double-stranded DNA was additive to the best phospholipid activators. These results support two types of activator sites on the enzyme: (i) lipid-phosphate ones close to the membrane interphase, and (ii) soluble (or particulate)-phosphate ones further out from the surface. Thereby, the nonbilayer (MGlcDAG) to bilayer (DGlcDAG) lipid balance may be integrated with the metabolic status of the cell and potentially also to membrane and cell division.

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Section: Discussionmentioning

confidence: 99%

The Nonbilayer/Bilayer Lipid Balance in Membranes

Vikström

Wieslander

2000

Journal of Biological Chemistry

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“…This number itself is in reasonable agreement with mea- The binding data also demonstrate that a large amount of spectrin (up to 23 wt% relative to lipid) is bound to the mixed lipid dispersions for which NMB data were obtained. It has been shown that the measured quadrupole splittings of head group deuterated phospholipids are sensitive to structural perturbations of the membrane surface [36,43,44]. Thus, the absence of any effect of bound spectrin on the quadrupolar splittings and Ti relaxation times indicates that no significant change in the DMPS-d3 conformation or dynamics of the DMPS head group are induced by the protein, even with a large amount of spectrin (23 wt% = 0.39 x 10m3 mol%) that is similar to the physiological spectrin-lipid ratio (1O-3 mol%) [7] in the inner leaflet of the erythrocyte membrane.…”

Section: Discussionmentioning

confidence: 99%

“…The presence of charged lipids such as DMPS [28], of ions [36] or of charged anaesthetics [37] near the deuterated head group of DMPC strongly modifies its conformation, as a result of the perturbation of the bilayer surface charge [43]. Partial neutralization or screening of DMPS charges by positive charges at the membrane surface allows the DMPC head group to recover its original conformation [22].…”

Section: Discussionmentioning

confidence: 99%

Weak interaction of spectrin with phosphatidylcholine‐phosphatidylserine multilayers: A ²H and ³¹P NMR study

et al. 1989

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Spectrin from human erythrocytes binds to bilayer dispersions of both DMPC and DMPSDMPC (I: 1, w/w). However, no effect of bound spectrin on the conformation of the lipid head groups, as measured from the deuterium quadrupolar splittings of DMPC or DMPS specifically deuterated in the polar head groups, was detected in I:1 mixtures of the two lipids containing either deuterated DMPC or DMPS. Neither the phase transition of the DMPS:DMPC mixtures, nor the spin-lattice relaxation time (T,) of the deuterated DMPS head group, was affected by spectrin. These results argue against any strong interaction of spectrin with phosphatidylserine and rule out the possibility that spectrin is responsible for the maintainance of PS in the inner monolayer of the erythrocyte membrane during the whole life-span of this cell.

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“…To this end, we employ the 'molecular electrometer' concept, according to which the changes in the C-H order parameters of the α and β carbons in the phospholipid head group (see Fig. 1) can be used to measure the ion affinity for a PC lipid bilayer 20,[29][30][31][32] . As the order parameters can be accurately measured in experiments and directly compared to simulations 33 , applying the molecular electrometer as a function of cation concentration allows the comparison of binding affinity between simulations and experiments.…”

Section: Introductionmentioning

confidence: 99%

Molecular electrometer and binding of cations to phospholipid bilayers

Catte

Girych

Javanainen

et al. 2016

Phys. Chem. Chem. Phys.

256

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Despite the vast amount of experimental and theoretical studies on the binding affinity of cations -especially the biologically relevant Na + and Ca 2+ -for phospholipid bilayers, there is no consensus in the literature. Here we show that by interpreting changes in the choline headgroup order parameters according to the 'molecular electrometer' concept [Seelig et al., Biochemistry, 1987, 26, 7535], one can directly compare the ion binding affinities between simulations and experiments. Our findings strongly support the view that in contrast to Ca 2+ and other multivalent ions, Na + and other monovalent ions (except Li + ) do not specifically bind to phosphatidylcholine lipid bilayers at sub-molar concentrations. However, the Na + binding affinity was overestimated by several molecular dynamics simulation models, resulting in artificially positively charged bilayers and exaggerated structural effects in the lipid headgroups. While qualitatively correct headgroup order parameter response was observed with Ca 2+ binding in all the tested models, no model had sufficient quantitative accuracy to interpret the Ca 2+ :lipid stoichiometry or the induced atomistic resolution structural changes. All scientific contributions to this open collaboration work were made publicly, using nmrlipids.blogspot.fi as the main communication platform.

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Phospholipid head groups as sensors of electric charge in membranes

Cited by 415 publications

References 61 publications

The Nonbilayer/Bilayer Lipid Balance in Membranes

The Nonbilayer/Bilayer Lipid Balance in Membranes

Weak interaction of spectrin with phosphatidylcholine‐phosphatidylserine multilayers: A ²H and ³¹P NMR study

Molecular electrometer and binding of cations to phospholipid bilayers

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Phospholipid head groups as sensors of electric charge in membranes

Cited by 415 publications

References 61 publications

The Nonbilayer/Bilayer Lipid Balance in Membranes

The Nonbilayer/Bilayer Lipid Balance in Membranes

Weak interaction of spectrin with phosphatidylcholine‐phosphatidylserine multilayers: A 2H and 31P NMR study

Molecular electrometer and binding of cations to phospholipid bilayers

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Weak interaction of spectrin with phosphatidylcholine‐phosphatidylserine multilayers: A ²H and ³¹P NMR study