Abstract:
:Recent experiments suggested that cholesterol and other lipid components of high negative spontaneous curvature facilitate membrane fusion. This is taken as evidence supporting the stalk-pore model of membrane fusion in which the lipid bilayers go through intermediate structures of high curvature. How do the high-curvature lipid components lower the free energy of the curved structure? Do the high-curvature lipid components modify the average spontaneous curvature of the relevant monolayer, thereby facilitate its bending, or do the lipid components redistribute in the curved structure so as to lower the free energy? This question is fundamental to the curvature elastic energy for lipid mixtures. Here we investigate the lipid distribution in a monolayer of a binary lipid mixture before and after bending, or more precisely in the lamellar, hexagonal, and distorted hexagonal phases. The lipid mixture is composed of 2:1 ratio of brominated di18:0PC and cholesterol. Using a newly developed procedure for the multiwavelength anomalous diffraction method, we are able to isolate the bromine distribution and reconstruct the electron density distribution of the lipid mixture in the three phases. We found that the lipid distribution is homogenous and uniform in the lamellar and hexagonal phases. But in the distorted hexagonal phase, the lipid monolayer has nonuniform curvature, and cholesterol almost entirely concentrates in the high curvature region. This finding demonstrates that the association energies between lipid molecules vary with the curvature of membrane. Thus, lipid components in a mixture may redistribute under conditions of nonuniform curvature, such as in the stalk structure. In such cases, the spontaneous curvature depends on the local lipid composition and the free energy minimum is determined by lipid distribution as well as curvature.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Wang W,Yang L,Huang HWdoi
10.1529/biophysj.106.097923subject
Has Abstractpub_date
2007-04-15 00:00:00pages
2819-30issue
8eissn
0006-3495issn
1542-0086pii
S0006-3495(07)71086-Xjournal_volume
92pub_type
杂志文章abstract::Single-molecule methods provide direct measurements of macromolecular dynamics, but are limited by the number of degrees of freedom that can be followed at one time. High-resolution rotor bead tracking (RBT) measures DNA torque, twist, and extension, and can be used to characterize the structural dynamics of DNA and d...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.11.017
更新日期:2018-01-23 00:00:00
abstract::THE THEORY OF ELECTROTONUS, WHICH HAS BEEN WELL DEVELOPED FOR SMALL CYLINDERS, IS EXTENDED: the fundamental potential equations for a membrane of arbitrary shape are derived, and solutions are found for cylindrical and spherical geometries. If two purely conductive media are separated by a resistance-capacitance membr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(68)86493-8
更新日期:1968-03-01 00:00:00
abstract::The energy transfer and charge separation kinetics of a photosystem I (PS I) core particle of an antenna size of 100 chlorophyll/P700 has been studied by combined fluorescence and transient absorption kinetics with picosecond resolution. This is the first combined picosecond study of transient absorption and fluoresce...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(93)81552-2
更新日期:1993-06-01 00:00:00
abstract::In Shaker-like channels, the activation gate is formed at the bundle crossing by the convergence of the inner S6 helices near a conserved proline-valine-proline motif, which introduces a kink that allows for electromechanical coupling with voltage sensor motions via the S4-S5 linker. Human ether-a-go-go-related gene (...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.01.035
更新日期:2014-03-04 00:00:00
abstract::De novo formation of cell pairs was used to examine the gating properties of single gap junction channels. Two separate cells of an insect cell line (clone C6/36, derived from the mosquito Aedes albopictus) were pushed against each other to provoke formation of gap junction channels. A dual voltage-clamp method was us...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(94)80521-1
更新日期:1994-08-01 00:00:00
abstract::In the outer hair cell (OHC), the extracisternal space (ECiS) is a conduit and reservoir of the molecular and ionic substrates of the lateral wall, including those necessary for electromotility. To determine the mechanisms through which molecules are transported in the ECiS of the OHC, we selectively imaged the time-d...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2009.06.011
更新日期:2009-08-19 00:00:00
abstract::When a light beam is focused on a muscle preparation which is allowed to contract, large changes in the intensity of the emerging light accompany the contraction. These movement-related optical signals were studied and compared to simultaneous measurements of force in isolated cardiac Purkinje fibers. The two signals ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(81)84843-6
更新日期:1981-04-01 00:00:00
abstract::The classical cable equation, in which membrane conductance is considered constant, is modified by including the linearized effect of membrane potential on sodium and potassium ionic currents, as formulated in the Hodgkin-Huxley equations for the squid giant axon. The resulting partial differential equation is solved ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(69)86446-5
更新日期:1969-10-01 00:00:00
abstract::Cellular differentiation proceeds along complicated pathways, even when it is induced by extracellular signaling molecules. One of the major reasons for this complexity is the highly multidimensional internal dynamics of cells, which sometimes causes apparently stochastic responses in individual cells to extracellular...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.10.002
更新日期:2014-11-18 00:00:00
abstract::We investigated the accessibility to protons and thiol-directed reagents of a cysteine substituted at position 338 in transmembrane segment 6 (TM6) of CFTR to test the hypothesis that T338 resides in the pore. Xenopus oocytes expressing T338C CFTR exhibited pH-dependent changes in gCl and I-V shape that were specific ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.050534
更新日期:2004-12-01 00:00:00
abstract::The spatiotemporal organization and dynamics of the plasma membrane and its constituents are central to cellular function. Fluorescence-based single-particle tracking has emerged as a powerful approach for studying the single molecule behavior of plasma-membrane-associated events because of its excellent background su...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2018.05.007
更新日期:2018-06-19 00:00:00
abstract::The relative contributions of the allosteric and affinity factors toward the change in p50 have been calculated for a series of effectors of hemoglobin (Hb). Shifts in the ligand affinity of deoxy Hb and the values for 50% ligand saturation (p50) were obtained from oxygen equilibrium data. Because the high-affinity pa...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(90)82556-X
更新日期:1990-03-01 00:00:00
abstract::Fatty acid binding proteins play an important role in the transportation of fatty acids. Despite intensive studies, how fatty acids enter the protein cavity for binding is still controversial. Here, a gap-closed variant of human intestinal fatty acid binding protein was generated by mutagenesis, in which the gap is lo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.12.005
更新日期:2020-01-21 00:00:00
abstract::Epithelial injury induces rapid recruitment of antimicrobial leukocytes to the wound site. In zebrafish larvae, activation of the epithelial NADPH oxidase Duox at the wound margin is required early during this response. Before injury, leukocytes are near the vascular region, that is, ∼100-300 μm away from the injury s...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.03.021
更新日期:2017-05-09 00:00:00
abstract::The bacterial flagellar motor is a rotary molecular machine that rotates the helical filaments that propel swimming bacteria. Extensive experimental and theoretical studies exist on the structure, assembly, energy input, power generation, and switching mechanism of the motor. In a previous article, we explained the ge...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2009.01.023
更新日期:2009-04-22 00:00:00
abstract::A novel system for measuring, simultaneously, ciliary beating and intracellular free calcium is presented. The advantages and dynamic nature of the system are demonstrated by measuring the effects of the calcium ionophore lonomycin and of extracellular ATP on ciliated rabbit trachea. The results are discussed with reg...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(94)80492-8
更新日期:1994-07-01 00:00:00
abstract::The strength of receptor-mediated cell adhesion is directly controlled by the mechanism of cohesive failure between the cell surface and underlying substrate. Unbinding can occur either at the locus of the specific bond or within the bilayer, which results in tearing the hydrophobic anchors from the membrane interior....
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)79990-8
更新日期:1995-09-01 00:00:00
abstract::Photoinduced electron transfer in photosystem I (PS I) proceeds from the excited primary electron donor P700 (a chlorophyll a dimer) via the primary acceptor A0 (chlorophyll a) and the secondary acceptor A1 (phylloquinone) to three [4Fe-4S] clusters, Fx, FA, and FB. Prereduction of the iron-sulfur clusters blocks elec...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(98)78023-3
更新日期:1998-06-01 00:00:00
abstract::Myoglobin (Mb) is a model system for ligand binding and migration. The energy barriers (ΔG) for ligand migration in Mb have been studied in the past by experiment and theory and significant differences between different approaches were found. From experiment, it is known that Mb can assume a large number of conformati...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.10.058
更新日期:2012-01-18 00:00:00
abstract::The viral genome and replicative enzymes of the human immunodeficiency virus are encased in a shell consisting of assembled mature capsid protein (CA). The core shell is a stable, effective protective barrier, but is also poised for dissolution on cue to allow transmission of the viral genome into its new host. In thi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)75725-6
更新日期:2001-07-01 00:00:00
abstract::A major challenge in synthetic gene delivery is to quantitatively predict the optimal design of polymer-based gene carriers (polyplexes). Here, we report a consistent, integrated, and fundamentally grounded computational methodology to address this challenge. This is achieved by accurately representing the spatio-temp...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.095521
更新日期:2007-02-01 00:00:00
abstract::Single-particle tracking is an important technique in the life sciences to understand the kinetics of biomolecules. The analysis of apparent diffusion coefficients in vivo, for example, enables researchers to determine whether biomolecules are moving alone, as part of a larger complex, or are bound to large cellular c...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2020.09.033
更新日期:2020-11-17 00:00:00
abstract::A-DNA is a stable alternative right-handed double helix that is favored by certain sequences (e.g., (dG)n.(dC)n) or under low humidity conditions. Earlier A-DNA structures of several DNA oligonucleotides and RNA.DNA chimeras have revealed some conformational variation that may be the result of sequence-dependent effec...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)79929-5
更新日期:1995-08-01 00:00:00
abstract::The mating pathway in Saccharomyces cerevisiae is one of the best understood signal transduction pathways in eukaryotes. It transmits the mating signal from plasma membrane into the nucleus through the G-protein coupled receptor and the mitogen-activated protein kinase (MAPK) cascade. According to current understandin...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.081661
更新日期:2006-12-01 00:00:00
abstract::A simple theoretical analysis shows that specificity of double-stranded DNA (dsDNA) targeting by homopyrimidine peptide nucleic acids (hpyPNAs) is a kinetically controlled phenomenon. Our computations give the optimum conditions for sequence-specific targeting of dsDNA by hpyPNAs. The analysis shows that, in agreement...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78918-5
更新日期:1997-06-01 00:00:00
abstract::The dynamics of protein distribution in endocytic membranes are relevant for many cellular processes, such as protein sorting, organelle and membrane microdomain biogenesis, protein-protein interactions, receptor function, and signal transduction. We have developed an assay based on Fluorescence Resonance Energy Micro...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74500-7
更新日期:2003-07-01 00:00:00
abstract::PIEZO1 is an inactivating eukaryotic cation-selective mechanosensitive ion channel. Two sites have been located in the channel that when individually mutated lead to xerocytotic anemia by slowing inactivation. By introducing mutations at two sites, one associated with xerocytosis and the other artificial, we were able...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2013.07.019
更新日期:2013-08-20 00:00:00
abstract::Aqueous proline solutions are deceptively simple as they can take on complex roles such as protein chaperones, cryoprotectants, and hydrotropic agents in biological processes. Here, a molecular level picture of proline/water mixtures is developed. Car-Parrinello ab initio molecular dynamics (CPAIMD) simulations of aqu...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.134916
更新日期:2008-12-01 00:00:00
abstract::In an attempt to quantitate the physical behavior of biological systems, Fourier analysis has been applied to the respiratory and circulatory systems by a number of investigators. The validity of this application has been questioned on the basis that these systems are nonlinear and not strictly periodic. If these obje...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(66)86657-2
更新日期:1966-05-01 00:00:00
abstract::Control of organelle abundance is a fundamental unsolved problem in cell biology. Mechanisms for number control have been proposed in which organelle assembly is actively increased or decreased to compensate for deviations from a set-point, but such phenomena have not been experimentally verified. In this report we ex...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.107052
更新日期:2007-09-01 00:00:00