Thermodynamic studies of bovine lung surfactant extract mixing with cholesterol and its palmitate derivative

Panda, Amiya Kumar; Nag, Kaushik; Harbottle, Robert R.; Possmayer, Fred; Petersen, Nils O.

doi:10.1016/j.jcis.2004.04.010

Cited by 18 publications

(21 citation statements)

References 34 publications

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“…Once these peptides have been inserted in membranes, which requires their central region to be hydrophobic enough, their amphipathic imbalance makes them two-dimensional equivalents of surfactants, for which the appropriate name linactant has recently been proposed. [95,96] In a process that is closely analogous to the formation of inverted micelles, these linactants can then aggregate to form pores, in which all their hydrophilic strips point toward the opening of the pore. [97] This event relies on a cooperative action of several peptides, thus providing (at least) a partial explanation for the experimentally observed strong sigmoidal (essentially threshold-like) dependence of antimicrobial activity as a function of peptide-lipid ratio.…”

Section: Pore-formation By Amphipathic Peptidesmentioning

confidence: 99%

Mesoscopic Membrane Physics: Concepts, Simulations, and Selected Applications

Deserno

2009

Macromol. Rapid Commun.

117

104

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The window of a few tens to a few hundred nanometers in length scale is a booming field in lipid membrane research, owing largely to two reasons. First, many exciting biophysical and cell biological processes take place within it. Second, experimental techniques manage to zoom in on this sub-optical scale, while computer simulations zoom out to system sizes previously unattainable, and both will be meeting soon. This paper reviews a selection of questions and concepts in this field and demonstrates that they can often be favorably addressed with highly simplified simulation models. Among the topics discussed are membrane adhesion to substrates, mixed lipid bilayers, lipid curvature coupling, pore formation by antimicrobial peptides, composition-driven protein aggregation, and curvature driven vesiculation.

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Section: Pore-formation By Amphipathic Peptidesmentioning

confidence: 99%

Mesoscopic Membrane Physics: Concepts, Simulations, and Selected Applications

Deserno

2009

Macromol. Rapid Commun.

117

104

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“…Similar experiments were carried out using the natural surfactant, BLES, which retains all of the polar and charged lipid content of natural surfactant (Yu et al 1983; Yu and Possmayer 1996) and in which 1–2 % of the dry weight is accounted for by the hydrophobic surfactant proteins SP-B and SP-C (Panda et al 2007; Zuo et al 2008). Earlier 2 H NMR observations of BLES doped with DPPC- d 62 showed spectra characteristic of axially symmetric reorientation, corresponding to liquid-crystalline behavior, above ~31 °C and broader spectra, characteristic of gel, below 20 °C (Nag et al 2006).…”

Section: Resultsmentioning

confidence: 84%

Effects of the lung surfactant protein B construct Mini-B on lipid bilayer order and topography

et al. 2012

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The hydrophobic lung surfactant protein, SP-B, is essential for survival. Cycling of lung volume during respiration requires a surface-active lipid–protein layer at the alveolar air–water interface. SP-B may contribute to surfactant layer maintenance and renewal by facilitating contact and transfer between the surface layer and bilayer reservoirs of surfactant material. However, only small effects of SP-B on phospholipid orientational order in model systems have been reported. In this study, N-terminal (SP-B8–25) and C-terminal (SP-B63–78) helices of SP-B, either linked as Mini-B or unlinked but present in equal amounts, were incorporated into either model phospholipid mixtures or into bovine lipid extract surfactant in the form of vesicle dispersions or mechanically oriented bilayer samples. Deuterium and phosphorus nuclear magnetic resonance (NMR) were used to characterize effects of these peptides on phospholipid chain orientational order, headgroup orientation, and the response of lipid–peptide mixtures to mechanical orientation by mica plates. Only small effects on chain orientational order or headgroup orientation, in either vesicle or mechanically oriented samples, were seen. In mechanically constrained samples, however, Mini-B and its component helices did have specific effects on the propensity of lipid–peptide mixtures to form unoriented bilayer populations which do not exchange with the oriented fraction on the timescale of the NMR experiment. Modification of local bilayer orientation, even in the presence of mechanical constraint, may be relevant to the transfer of material from bilayer reservoirs to a flat surface-active layer, a process that likely requires contact facilitated by the formation of highly curved protrusions.

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“…The calculated number for complete cholesterol ester peak at 671 m/z is very small as well as contained an Na ion and was difficult to detect in MALDI-TOF of LDL 33 . A more recent study has shown that cholesterol esters are more potent inhibitors of BLES than free cholesterol 45 .…”

Section: Cholesterol and Lung Surfactantmentioning

confidence: 99%

“…Although these studies do not suggest any clear cut mechanism of bilayer interactions of LDL and serum with BLES, our Raman data clearly suggest possibilities of different modes of interaction of these serum materials with BLES compared to cholesterol in normal or excess amounts. It is possible that the apo-proteins present in LDL as well as serum soluble proteins such as albumin and others could have probably interacted with SP-B/SP-C present in BLES and thus causes the changes in BLES bilayers, other than the effects already induced by cholesterol or its esters 45 . There may possibly be a dual mechanism involved here requiring further investigation with serum or LDL protein components.…”

Section: Bilayer Phase Changesmentioning

confidence: 99%