The Charge Properties of Phospholipid Nanodiscs

Cheng Her, Dana I. Filoti, Mark A. McLean, Stephen G. Sligar, J. B. Alexander Ross, Harmen Steele, Thomas M. Laue

Research output: Contribution to journalArticle

Abstract

Phospholipids (PLs) are a major, diverse constituent of cell membranes. PL diversity arises from the nature of the fatty acid chains, as well as the headgroup structure. The headgroup charge is thought to contribute to both the strength and specificity of protein-membrane interactions. Because it has been difficult to measure membrane charge, ascertaining the role charge plays in these interactions has been challenging. Presented here are charge measurements on lipid Nanodiscs at 20°C in 100 mM NaCl, 50 mM Tris, at pH 7.4. Values are also reported for measurements made in the presence of Ca2+ and Mg2+ as a function of NaCl concentration, pH, and temperature, and in solvents containing other types of cations and anions. Measurements were made for neutral (phosphatidylcholine and phosphatidylethanolamine) and anionic (phosphatidylserine, phosphatidic acid, cardiolipin, and phosphatidylinositol 4,5-bisphosphate (PIP2)) PLs containing palmitoyl-oleoyl and dimyristoyl fatty acid chains. In addition, charge measurements were made on Nanodiscs containing an Escherichia coli lipid extract. The data collected reveal that 1) POPE is anionic and not neutral at pH 7.4; 2) high-anionic-content Nanodiscs exhibit polyelectrolyte behavior; 3) 3 mM Ca2+ neutralizes a constant fraction of the charge, but not a constant amount of charge, for POPS and POPC Nanodiscs; 4) in contrast to some previous work, POPC only interacts weakly with Ca2+; 5) divalent cations interact with lipids in a lipid- and ion-specific manner for POPA and PIP2 lipids; and 6) the monovalent anion type has little influence on the lipid charge. These results should help eliminate inconsistencies among data obtained using different techniques, membrane systems, and experimental conditions, and they provide foundational data for developing an accurate view of membranes and membrane-protein interactions.

Original languageEnglish (US)
Pages (from-to)989-998
Number of pages10
JournalBiophysical journal
Volume111
Issue number5
DOIs
StatePublished - Sep 6 2016

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Phospholipids
Lipids
Anions
Membranes
Membrane Proteins
Fatty Acids
Phosphatidic Acids
Cardiolipins
Phosphatidylserines
Divalent Cations
Phosphatidylinositols
Phosphatidylcholines
Cations
Cell Membrane
Ions
Escherichia coli
Temperature

ASJC Scopus subject areas

  • Biophysics

Cite this

Her, C., Filoti, D. I., McLean, M. A., Sligar, S. G., Alexander Ross, J. B., Steele, H., & Laue, T. M. (2016). The Charge Properties of Phospholipid Nanodiscs. Biophysical journal, 111(5), 989-998. https://doi.org/10.1016/j.bpj.2016.06.041

The Charge Properties of Phospholipid Nanodiscs. / Her, Cheng; Filoti, Dana I.; McLean, Mark A.; Sligar, Stephen G.; Alexander Ross, J. B.; Steele, Harmen; Laue, Thomas M.

In: Biophysical journal, Vol. 111, No. 5, 06.09.2016, p. 989-998.

Research output: Contribution to journalArticle

Her, C, Filoti, DI, McLean, MA, Sligar, SG, Alexander Ross, JB, Steele, H & Laue, TM 2016, 'The Charge Properties of Phospholipid Nanodiscs', Biophysical journal, vol. 111, no. 5, pp. 989-998. https://doi.org/10.1016/j.bpj.2016.06.041
Her C, Filoti DI, McLean MA, Sligar SG, Alexander Ross JB, Steele H et al. The Charge Properties of Phospholipid Nanodiscs. Biophysical journal. 2016 Sep 6;111(5):989-998. https://doi.org/10.1016/j.bpj.2016.06.041
Her, Cheng ; Filoti, Dana I. ; McLean, Mark A. ; Sligar, Stephen G. ; Alexander Ross, J. B. ; Steele, Harmen ; Laue, Thomas M. / The Charge Properties of Phospholipid Nanodiscs. In: Biophysical journal. 2016 ; Vol. 111, No. 5. pp. 989-998.
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