Abstract:
:Despite the importance of lipid rafts, commonly defined as liquid-ordered domains rich in cholesterol and in lipids with high gel-to-fluid melting temperatures (T(m)), the rules for raft formation in membranes are not completely understood. Here, a fluorescence-quenching strategy was used to define how lipids with low T(m), which tend to form disordered fluid domains at physiological temperatures, can stabilize ordered domain formation by cholesterol and high-T(m) lipids (either sphingomyelin or dipalmitoylphosphatidylcholine). In bilayers containing mixtures of low-T(m) phosphatidylcholines, cholesterol, and high-T(m) lipid, the thermal stability of ordered domains decreased with the acyl-chain structure of low-T(m) lipids in the following order: diarachadonyl > diphytanoyl > 1-palmitoyl 2-docosahexenoyl = 1,2 dioleoyl = dimyristoleoyl = 1-palmitoyl, 2-oleoyl (PO). This shows that low-T(m) lipids with two acyl chains having very poor tight-packing propensities can stabilize ordered domain formation by high-T(m) lipids and cholesterol. The effect of headgroup structure was also studied. We found that even in the absence of high-T(m) lipids, mixtures of cholesterol with PO phosphatidylethanolamine (POPE) and PO phosphatidylserine (POPS) or with brain PE and brain PS showed a (borderline) tendency to form ordered domains. Because these lipids are abundant in the inner (cytofacial) leaflet of mammalian membranes, this raises the possibility that PE and PS could participate in inner-leaflet raft formation or stabilization. In bilayers containing ternary mixtures of PO lipids, cholesterol, and high-T(m) lipids, the thermal stability of ordered domains decreased with the polar headgroup structure of PO lipids in the order PE > PS > phosphatidylcholine (PC). Analogous experiments using diphytanoyl acyl chain lipids in place of PO acyl chain lipids showed that the stabilization of ordered lipid domains by acyl chain and headgroup structure was not additive. This implies that it is likely that there are two largely mutually exclusive mechanisms by which low-T(m) lipids can stabilize ordered domain formation by high-T(m) lipids and cholesterol: 1), by having structures resulting in immiscibility of low-T(m) and high-T(m) lipids, and 2), by having structures allowing them to pack tightly within ordered domains to a significant degree.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Bakht O,Pathak P,London Edoi
10.1529/biophysj.107.114967subject
Has Abstractpub_date
2007-12-15 00:00:00pages
4307-18issue
12eissn
0006-3495issn
1542-0086pii
S0006-3495(07)71683-1journal_volume
93pub_type
杂志文章abstract::Methods are described for discrimination of models of the gating kinetics and permeation of single ionic channels. Both maximum likelihood and regression procedures are discussed. In simple situations, where models are nested, standard hypothesis tests can be used. More commonly, however, non-nested models are of inte...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(87)83331-3
更新日期:1987-02-01 00:00:00
abstract::Collective action by inverse-Bin/Amphiphysin/Rvs (I-BAR) domains drive micron-scale membrane remodeling. The macroscopic curvature sensing and generation behavior of I-BAR domains is well characterized, and computational models have suggested various mechanisms on simplified membrane systems, but there remain missing ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2020.11.019
更新日期:2021-01-05 00:00:00
abstract::In skeletal muscle, excitation-contraction coupling involves the activation of dihydropyridine receptors (DHPR) and type-1 ryanodine receptors (RyR1) to produce depolarization-dependent sarcoplasmic reticulum Ca²⁺ release via orthograde signaling. Another form of DHPR-RyR1 communication is retrograde signaling, in whi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.04.012
更新日期:2011-05-18 00:00:00
abstract::We investigated self-adhesion between highly negatively charged aggrecan macromolecules extracted from bovine cartilage extracellular matrix by performing atomic force microscopy (AFM) imaging and single-molecule force spectroscopy (SMFS) in saline solutions. By controlling the density of aggrecan molecules on both th...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.09.002
更新日期:2010-11-17 00:00:00
abstract::We present MEMLET (MATLAB-enabled maximum-likelihood estimation tool), a simple-to-use and powerful program for utilizing maximum-likelihood estimation (MLE) for parameter estimation from data produced by single-molecule and other biophysical experiments. The program is written in MATLAB and includes a graphical user ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2016.06.019
更新日期:2016-07-26 00:00:00
abstract::Low frequency audible vibrations are produced by human skeletal muscles undergoing sustained contraction. The effect is easily demonstrable with an electronic stethoscope which amplifies sound below 50 Hz. Autocorrelation analysis of the signal shows that it is periodic with a frequency 25 +/- 2.5 Hz. The quality of t...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(80)85080-6
更新日期:1980-04-01 00:00:00
abstract::Molecular diffusion process after the photo-induced electron injection to ferric cytochrome c (Fe(III) cyt c) in guanidine hydrochloride (GdnHCl) 3.5 M buffer solution is studied by the time-resolved transient grating technique. Circular dichroism studies have revealed that Fe(III) cyt c is unfolded under this conditi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74615-3
更新日期:2003-09-01 00:00:00
abstract::The detection of the 1H NMR signal of myoglobin (Mb) in tissue opens an opportunity to examine its cellular diffusion property, which is central to its purported role in facilitating oxygen transport. In perfused myocardium the field-dependent transverse relaxation analysis of the deoxy Mb proximal histidyl NdeltaH in...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78305-X
更新日期:1997-11-01 00:00:00
abstract::We demonstrate a novel method for stretching a long DNA molecule in agarose gel with alternating current (AC) electric fields. The molecular motion of a long DNA (T4 DNA; 165.6 kb) in agarose gel was studied using fluorescence microscopy. The effects of a wide range of field frequencies, field strengths, and gel conce...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)75398-8
更新日期:2002-01-01 00:00:00
abstract::Cells in a cloned population of coliform bacteria exhibit a wide range of swimming behaviors--a form of non-genetic individuality. We used computer models to examine the proposition that these variations are due to differences in the number of chemotaxis signaling molecules from one cell to the next. Simulations were ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(98)77777-X
更新日期:1998-01-01 00:00:00
abstract::A lattice relaxation algorithm is developed to solve the Poisson-Nernst-Planck (PNP) equations for ion transport through arbitrary three-dimensional volumes. Calculations of systems characterized by simple parallel plate and cylindrical pore geometries are presented in order to calibrate the accuracy of the method. A ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(99)77232-2
更新日期:1999-02-01 00:00:00
abstract::We have measured the electronic circular dichroism (ECD) of the ferri- and ferro-states of several natural cytochrome c derivatives (horse heart, chicken, bovine, and yeast) and the Y67F mutant of yeast in the region between 300 and 750 nm. Thus, we recorded the ECD of the B- and Q-band region as well as the charge-tr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.095976
更新日期:2007-02-01 00:00:00
abstract::A voltage clamp study has been performed in the presynaptic terminal of the squid stellate ganglion. After blockage of the voltage-dependent sodium and potassium conductances, an inward calcium current is demonstrated. Given a step-depolarization pulse, this voltage- and time-dependent conductance has an S-shaped onse...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(81)84898-9
更新日期:1981-03-01 00:00:00
abstract::Neutron scattering and nuclear magnetic resonance relaxation experiments are combined with molecular dynamics (MD) simulations in a novel, to our knowledge, approach to investigate the change in internal dynamics on substrate (camphor) binding to a protein (cytochrome P450cam). The MD simulations agree well with both ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2012.10.013
更新日期:2012-11-21 00:00:00
abstract::The cell membrane of Valonia utricularis contains an electrogenic carrier system for chloride (Wang et al., Biophys J. 59:235-248 (1991)). The electrical impedance of V. utricularis was measured in the frequency range between 1 Hz and 50 kHz. The analysis of the impedance spectra from V. utricularis and its comparison...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(94)80631-9
更新日期:1994-10-01 00:00:00
abstract::We previously used an orthogonal high-throughput screen to select peptides that spontaneously cross synthetic lipid bilayers without bilayer disruption. Many of the 12-residue spontaneous membrane translocating peptides (SMTPs) selected from the library contained a 5-residue consensus motif, LRLLR in positions 5-9. We...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.06.070
更新日期:2017-08-22 00:00:00
abstract::Using molecular dynamics simulations, we studied the mode of association of the cell-penetrating peptide penetratin with both a neutral and a charged bilayer. The results show that the initial peptide-lipid association is a fast process driven by electrostatic interactions. The homogeneous distribution of positively c...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.052787
更新日期:2005-02-01 00:00:00
abstract::We aimed to investigate insulin amyloid fibril polymorphism caused by salt effects and heating temperature and to visualize the structural differences of the polymorphisms in situ using Raman imaging without labeling. The time course monitoring for amyloid formation was carried out in an acidic condition without any s...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2020.04.031
更新日期:2020-06-16 00:00:00
abstract::ATP-sensitive K(+)-channels link metabolism and excitability in neurons, myocytes, and pancreatic islets. Mutations in the pore-forming subunit (Kir6.2; KCNJ11) cause neonatal diabetes, developmental delay, and epilepsy by decreasing sensitivity to ATP inhibition and suppressing electrical activity. Mutations of resid...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.138685
更新日期:2008-11-15 00:00:00
abstract::With their longest dimension typically being less than 100 nm, molecular motors are significantly below the optical-resolution limit. Despite substantial advances in fluorescence-based imaging methodologies, labeling with beads remains critical for optical-trapping-based investigations of molecular motors. A key exper...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2016.05.015
更新日期:2016-06-21 00:00:00
abstract::Nonphotochemical quenching is the protective mechanism against overexcitation of photosystem II, triggered by excess ΔpH in photosynthetic membranes. The light-harvesting complexes (LHCs), the de-epoxidation of violaxanthin to zeaxanthin, and the photosystem II subunit S (PsbS) work in synergy for an optimized multile...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.09.034
更新日期:2017-12-05 00:00:00
abstract::A simple method of simulating cell kinetics experiments, suitable for use on small generally available computers and capable of any degree of accuracy without increase of store required, is described. No assumption is necessary as to cycle-time distribution; the computer program, after being adjusted to generate perce...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(72)86172-1
更新日期:1972-11-01 00:00:00
abstract::Lateral organization of cholesterol in dioleoyl-phosphatidylcholine (DOPC) lipid bilayers at high cholesterol concentration (>45 mol%) was investigated using steady-state fluorescence anisotropy and fluorescent resonance energy transfer techniques. The recently devised Low Temperature Trap method was used to prepare c...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(04)74221-6
更新日期:2004-03-01 00:00:00
abstract::Proteins are not rigid molecules, but exhibit internal motions on timescales ranging from femto- to milliseconds and beyond. In solution, proteins also experience global translational and rotational motions, sometimes on timescales comparable to those of the internal fluctuations. The possibility that internal and glo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.05.041
更新日期:2011-07-06 00:00:00
abstract::This contribution describes measurements of lipid bilayer domain line tension based on two-dimensional thermal undulations of membranes with liquid ordered/liquid disordered phase coexistence and near-critical composition at room temperature. Lateral inhomogeneity of lipid and protein composition is currently a subjec...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.111922
更新日期:2007-11-01 00:00:00
abstract::Previous data as well as new results are examined with a view to determining the boundary conditions which present experimental information places on a satisfactory polypeptide chain model for the structure of feather keratin. Our studies indicate these conditions to include the following: (1) A 189 A identity period,...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/s0006-3495(61)86903-8
更新日期:1961-07-01 00:00:00
abstract::Bacterial endotoxins (lipopolysaccharides (LPS)) are strong elicitors of the human immune system by interacting with serum and membrane proteins such as lipopolysaccharide-binding protein (LBP) and CD14 with high specificity. At LPS concentrations as low as 0.3 ng/ml, such interactions may lead to severe pathophysiolo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.04.041
更新日期:2011-06-08 00:00:00
abstract::Some plant leaves display complex, orientation-dependent, proton nuclear magnetic resonance (1H NMR) spectra. The spectral patterns vary as the angle between the leaf surface and the applied magnetic field is varied. They also vary with temperature and with the quantity of absorbed manganous ions, but they are indepen...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(85)83826-1
更新日期:1985-11-01 00:00:00
abstract::Rapid and robust methods are required to quantify the effect of hydrodynamic shear on protein conformation change. We evaluated such strategies in this work and found that the binding of the fluorescent probe 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (bis-ANS) to hydrophobic pockets in the blood protein von ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2009.08.023
更新日期:2009-11-04 00:00:00
abstract::Negatively charged phospholipids are an important component of biological membranes. The thermodynamic parameters governing self-assembly of anionic phospholipids are deduced here from isothermal titration calorimetry. Heats of demicellization were determined for dioctanoyl phosphatidylglycerol (PG) and phosphatidylse...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2012.01.049
更新日期:2012-03-07 00:00:00