Regional Cooperativity in the Phase Transitions of Dipalmitoylphosphatidylcholine Bilayers: The Lipid Tail Triggers the Isothermal Crystallization Process

Wu, Fugen; Jia, Qi; Wu, Rui-Guang; Yu, Zhi‐Wu

doi:10.1021/jp200733y

Cited by 38 publications

(49 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To the best of our knowledge, no one has measured the main phase transition temperature (T m ) of a pure DPPC simulation using the CHARMM36 lipid force field parameters. Using other force fields, T m has been suggested to be between 300 and 320 K [52,53], which compares fairly well to the experimental temperatures of 314–315 K [54,55]. Our pure DPPC membranes are gel-like and order parameters show the DPPC bilayers to be slightly less ordered than the cholesterol-containing bilayers (see Supplemental Figure 3).…”

Section: Methodssupporting

confidence: 81%

Characterization of the water defect at the HIV-1 gp41 membrane spanning domain in bilayers with and without cholesterol using molecular simulations

Baker

Gangupomu²,

Abrams

2014

Biochimica et Biophysica Acta (BBA) - Biomembranes

View full text Add to dashboard Cite

The membrane spanning domain (MSD) of human immunodeficiency virus 1 (HIV-1) envelope glycoprotein gp41 is important for fusion and infection. We used molecular dynamics (MD) simulations (3.4 μs total) to relate membrane and peptide properties that lead to water solvation of the α-helical gp41 MSD’s midspan arginine in pure dipalmitoylphosphatidylcholine (DPPC) and in 50/50 DPPC/cholesterol membranes. We find that the midspan arginine is solvated by water that penetrates the inner leaflet, leading to a so-called water defect. The water defect is surprisingly robust across initial conditions and membrane compositions, but the presence of cholesterol modulates its behavior in several key ways. In the cholesterol-containing membranes, fluctuations in membrane thickness and water penetration depth are localized near the midspan arginine, and the MSD helices display a tightly regulated tilt angle. In the cholesterol-free membranes, thickness fluctuations are not as strongly correlated to the peptide position and tilt angles vary significantly depending on protein position relative to boundaries between domains of differing thickness. Cholesterol in an HIV-1 viral membrane is required for infection. Therefore, this work suggests that the colocalized water defect and membrane thickness fluctuations in cholesterol-containing viral membranes play an important role in fusion by bringing the membrane closer to a stability limit that must be crossed for fusion to occur.

show abstract

Section: Methodssupporting

confidence: 81%

Characterization of the water defect at the HIV-1 gp41 membrane spanning domain in bilayers with and without cholesterol using molecular simulations

Baker

Gangupomu²,

Abrams

2014

Biochimica et Biophysica Acta (BBA) - Biomembranes

View full text Add to dashboard Cite

show abstract

“…2), which can reflect the packing state of the lipid hydrocarbon tails. 14,21,22 For the P β phase at 35 o C, the q m resides at 14.9 nm -1 , corresponding to a d value of 0.427 nm. 2A) show that at 10 o C, the L β phase has a single sharp peak (the peak of the scattering vector) at q m = 14.9 nm -1 .…”

Section: Resultsmentioning

confidence: 99%

Molecular-level pictures of the phase transitions of saturated and unsaturated phospholipid binary mixtures

Sun

Zhou

et al. 2015

RSC Adv.

Self Cite

View full text Add to dashboard Cite

Binary lipid mixtures consisting of saturated and unsaturated lipids are important models for natural cell membranes. However, a detailed molecular picture for the phase transition process of such lipid binary mixtures remains unclear. Herein, by using deuterated dipalmitoylphosphatidylcholine (DPPC-d 62 ) and hydrogenated dioleoylphosphatidic acid (DOPA), we expect to analyze separately the changes of the two lipid components during thermotropic phase transitions by temperature-dependent Fourier transform infrared (FTIR) spectroscopy, and uncover the hidden secrets of a seemingly single endothermic peak observed in differential scanning calorimetry (DSC) experiments. We found that at low DOPA concentrations (10-20 mol%), a gel to fluid conformational transition of DPPC-d 62 and a fluidization transition of DOPA by DPPC-d 62 were observed. The two lipids were found to have nonsynchronous conformational rearrangements in the tail regions upon thermotropic phase transitions, with the change of DOPA earlier than DPPC-d 62 . Besides, in the mixed fluid phase at 40 ºC, the unsaturated DOPA can be fluidized (loosened) by the saturated DPPC-d 62 , and such an isothermal fluidization effect is more pronounced at elevated DPPC-d 62 concentrations. At higher DOPA contents (30-50 mol %), only DPPC-d 62 molecules have conformational transitions upon heating. The present work demonstrates for the first time that the unsaturated lipid component can have significant conformational reorganizations in the phase transition process of a saturated-unsaturated binary lipid mixture.

show abstract

“…On the one hand, for all the mixtures containing diC8PC, the DSC curves show the disappearance of the pre-transition peak at around 38 C compared to DPPC, which is the phase transition from the lamellar gel phase (L b 0 ) to the rippled gel phase (P b 0 ). 32 The disappearance of the pre-transition of DPPC is also seen in other systems when another component, for example, DOPA, is added. 34 On the other hand, there are differences in the DSC curves between the mixtures containing diC8PC, depending on the q values.…”

Section: 48mentioning

confidence: 94%

Phase behavior of a binary lipid system containing long- and short-chain phosphatidylcholines

Sun

et al. 2017

RSC Adv.

Self Cite

View full text Add to dashboard Cite

Bilayered micelles, or so-called bicelles, are generally made of long-and short-chain lipids. They are extensively used as model membranes to study the structure of membrane-associated peptides or proteins and their interactions with membranes. However, the phase behavior of lipid mixtures composed of longand short-chain lipids, especially at low temperatures, is still not very clear. In this work, the most commonly used long-chain lipid, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and a short-chain lipid, 1,2-dioctanoyl-sn-glycero-3-phosphocholine (diC8PC), were selected as a bicellar model to study their phase behavior. Over the whole range of DPPC/diC8PC molar ratios (q) studied in this work, a lamellar crystalline phase (L c 0 ) enriched in DPPC was found to be the most stable phase at 5 C, together with a diC8PC-enriched micelle phase. Interestingly, a metastable phase, named the U phase in this work, was observed in the mixtures with a DPPC/diC8PC molar ratio between 1 and 4. The metastable U phase was found to be lacking in long-range order in the direction of the bilayer surface normal, but bearing a different "crystalline phase-like" hydrocarbon chain packing mode, in comparison with the lamellar crystalline phase. The kinetic properties of the U phase were also studied in detail, and it was found that the phase acts as a precursor phase in the process of forming the most stable crystalline phase. This work deepens our understanding of lipid crystallization behavior, and is also a step forward towards a more detailed picture of the phase behavior of lipid mixtures composed of long-and short-chain lipids.

show abstract

Regional Cooperativity in the Phase Transitions of Dipalmitoylphosphatidylcholine Bilayers: The Lipid Tail Triggers the Isothermal Crystallization Process

Cited by 38 publications

References 74 publications

Characterization of the water defect at the HIV-1 gp41 membrane spanning domain in bilayers with and without cholesterol using molecular simulations

Characterization of the water defect at the HIV-1 gp41 membrane spanning domain in bilayers with and without cholesterol using molecular simulations

Molecular-level pictures of the phase transitions of saturated and unsaturated phospholipid binary mixtures

Phase behavior of a binary lipid system containing long- and short-chain phosphatidylcholines

Contact Info

Product

Resources

About