Abstract:
:It was previously reported (Chernomordik and Sowers, 1991) that erythrocyte ghosts which were exposed to a 42 degrees C, 10-min heat treatment would, upon electrofusion, produce over 15-20 s a fusion product with an "open lumen" (i.e., the fusion product became converted to one large sphere), while electrofusion of ghost membranes not so exposed would lead to chains of polyghosts. In phase optics the chains of polyghosts showed a "flat diaphragm" at virtually every ghost-ghost junction (i.e., the ghosts do not appear to be fused even though fluorescent-labeled lipid analogs can laterally diffuse from a labeled ghost to an adjacent unlabeled ghost). In the present study we found that the diameter increase in open lumen- and flat diaphragm-producing fusion processes both had a rapid but short early phase (0-5 s after fusion) which was exponential or nearly so and a slow but long late phase (5-120 s after fusion) which was essentially linear. Heat treatments at 39 or 42 degrees C caused a minor acceleration in only the late phase, while temperatures of 45 or 50 degrees C caused an immediate and dramatic acceleration in the rate of diameter increase (spheres in 1-2 s). Ghost membranes in the presence of glycerol at 20% (v/v) did not form open lumens when exposed to the 42 degrees C (but not the > or = 45 degrees C) heat treatment. This suggested that the heat treatment was denaturing a critical protein. Both of these observations are consistent with the involvement of the spectrin network since it is the only protein in the erythrocyte membrane which is known (Brandts et al., 1977) to have a calorimetric transition over the same temperature range used in our heat treatments. The diameter versus time curves were sensitive to: (i) the residual effects of the fusogenic electric pulse only up to about 1 s after the pulse, (ii) the strength of the dielectrophoretic field after the pulse, but not before the pulse,(iii) the ambient temperature during the measurement.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Wu Y,Sjodin RA,Sowers AEdoi
10.1016/S0006-3495(94)80762-3subject
Has Abstractpub_date
1994-01-01 00:00:00pages
114-9issue
1eissn
0006-3495issn
1542-0086pii
S0006-3495(94)80762-3journal_volume
66pub_type
杂志文章abstract::The four-alpha-helix bundle mimics the transmembrane domain of the Cys-loop receptor family believed to be the protein target for general anesthetics. Using high resolution NMR, we solved the structure (Protein Data Bank ID: 2I7U) of a prototypical dimeric four-alpha-helix bundle, (Aalpha(2)-L1M/L38M)(2,) with designe...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.117838
更新日期:2008-06-01 00:00:00
abstract::The plasma membrane of cells has a complex architecture based on the bidimensional liquid-crystalline bilayer arrangement of phospho- and sphingolipids, which in turn embeds several proteins and is connected to the cytoskeleton. Several studies highlight the spatial membrane organization into more ordered (Lo or lipid...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2018.11.3141
更新日期:2019-02-05 00:00:00
abstract::This study presents what is, to our knowledge, a novel technique by means of which the ratio of the single gating charges of voltage-gated rat brain IIA (rBIIA) sodium and Shaker potassium ion channels was estimated. In the experiment, multiple tandems of enhanced green fluorescent protein were constructed and inserte...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.130765
更新日期:2008-08-01 00:00:00
abstract::Cardiac excitation-contraction coupling is initialized by the release of Ca from the sarcoplasmic reticulum (SR) in response to a sudden increase in local cytosolic [Ca] ([Ca]i) within the junctional cleft. We have tested the hypothesis that functional ryanodine receptor (RyR) regulation plays a major role in the regu...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.068734
更新日期:2005-12-01 00:00:00
abstract::Structure-function studies of the Cys loop family of ionotropic neurotransmitter receptors (GABA, nACh, 5-HT(3), and glycine receptors) have resulted in a six-loop (A-F) model of the agonist-binding site. Key amino acids have been identified in these loops that associate with, and stabilize, bound ligand. The next ste...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2008.09.011
更新日期:2009-01-01 00:00:00
abstract::Nuclear transport receptors (NTRs) mediate nucleocytoplasmic transport via their affinity for unstructured proteins (polymers) in the nuclear pore complex (NPC). Here, we have modeled the effect of NTRs on polymeric structure in the nanopore confinement of the NPC central conduit. The model explicitly takes into accou...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2013.11.013
更新日期:2013-12-17 00:00:00
abstract::Label-free imaging techniques such as differential interference contrast (DIC) allow the observation of cells and large subcellular structures in their native, unperturbed states with minimal exposure to light. The development of robust computational image-analysis routines is vital to quantitative label-free imaging....
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2020.12.013
更新日期:2021-01-11 00:00:00
abstract::Dendrites of cerebellar Purkinje cells (PCs) respond to brief excitations from parallel fibers with lasting plateau depolarizations. It is unknown whether these plateaus are local events that boost the synaptic signals or they propagate to the soma and directly take part in setting the cell firing dynamics. To address...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.04.056
更新日期:2010-07-21 00:00:00
abstract::We have measured the static magnetization of unreduced and reduced reaction centers that vary in their quinone content. Measurements were performed in the temperature range 0.7 degrees K less than T less than 200 degrees K and magnetic fields of up to 10 kG. The electronic g-value, crystal field parameters D, E, and t...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(80)85030-2
更新日期:1980-12-01 00:00:00
abstract::One theory of freezing damage suggests that slowly cooled cells are killed by being exposed to increasing concentrations of electrolytes as the suspending medium freezes. A corollary to this view is that protective additives such as glycerol protect cells by acting colligatively to reduce the electrolyte concentration...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(78)85436-8
更新日期:1978-07-01 00:00:00
abstract::The two glycosphingolipids galactosylceramide (GalC) and its sulfated form, cerebroside sulfate (CBS), are present at high concentrations in the multilayered myelin sheath and are involved in carbohydrate-carbohydrate interactions between the lipid headgroups. In order to study the structure of the complex of these tw...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76645-8
更新日期:2000-02-01 00:00:00
abstract::The giant protein titin is responsible for the elasticity of nonactivated muscle sarcomeres. Titin-based passive stiffness in myocardium is modulated by titin-isoform switching and protein-kinase (PK)A- or PKG-dependent titin phosphorylation. Additional modulatory effects on titin stiffness may arise from disulfide bo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2009.05.037
更新日期:2009-08-05 00:00:00
abstract::Cord factor (trehalose 6,6'-dimycolate, CF) is a glycolipid located in the outer mycobacterial cell wall that is implicated in the pathogenesis of mycobacteria. Furthermore, CF is a convenient model for studying mycolic acid residues, the major lipid constituents of the mycobacterial cell wall that are believed to for...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79523-1
更新日期:1996-12-01 00:00:00
abstract::Cryo-electron microscopy is rapidly emerging as a powerful technique to determine the structures of complex macromolecular systems elusive to other techniques. Because many of these systems are highly dynamical, characterizing their movements is also a crucial step to unravel their biological functions. To achieve thi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2018.02.028
更新日期:2018-04-10 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::The aquaglyceroporin GlpF is a transmembrane channel of Escherichia coli that facilitates the uptake of glycerol by the cell. Its high glycerol uptake rate is crucial for the cell to survive in very low glycerol concentrations. Although GlpF allows both influx and outflux of glycerol, its structure, similar to the str...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74718-3
更新日期:2003-11-01 00:00:00
abstract::Historically, predicting macroscopic blood flow characteristics such as viscosity has been an empirical process due to the difficulty in rigorously including the particulate nature of blood in a mathematical representation of blood rheology. Using a two-dimensional lattice Boltzmann approach, we have simulated the flo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.051151
更新日期:2005-03-01 00:00:00
abstract::To the best of our knowledge, this is the first report on the structure of product-inhibited mammalian peroxidase. Lactoperoxidase is a heme containing an enzyme that catalyzes the inactivation of a wide range of microorganisms. In the presence of hydrogen peroxide, it preferentially converts thiocyanate ion into a to...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2008.09.019
更新日期:2009-01-01 00:00:00
abstract::Pre-mRNA processing protein 40 (Prp40) is a nuclear protein that has a role in pre-mRNA splicing. Prp40 possesses two leucine-rich nuclear export signals, but little is known about the function of Prp40 in the export process. Another protein that has a role in protein export is centrin, a member of the EF-hand superfa...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.03.042
更新日期:2017-06-20 00:00:00
abstract::The α-helical (AH) domain of the hepatitis C virus nonstructural protein NS5A, anchored at the cytoplasmic leaflet of the endoplasmic reticulum, plays a role in viral replication. However, the peptides derived from this domain also exhibit remarkably broad-spectrum virocidal activity, raising questions about their mod...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2015.11.032
更新日期:2016-01-05 00:00:00
abstract::Actin is ubiquitous globular protein that polymerizes into filaments and forms networks that participate in the force generation of eukaryotic cells. Such forces are used for cell motility, cytokinesis, and tissue remodeling. Among those actin networks, we focus on the actin cortex, a dense branched network beneath th...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.07.008
更新日期:2014-08-19 00:00:00
abstract::Five highly homologous epidermal growth factor receptor ligands were studied by mass spectral analysis, hydrogen/deuterium (H/D) exchange via attenuated total reflectance Fourier transform-infrared spectroscopy, and two-dimensional correlation analysis. These studies were performed to determine the order of events dur...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.125856
更新日期:2008-05-15 00:00:00
abstract::The two-microelectrode, voltage-clamp technique was applied to rabbit cardiac Purkinje fibers to study the interaction of tetrodotoxin (TTX) with the slowly inactivating Na current. Binding of TTX to rested, inactivated, and activated channels was estimated by measuring the relative decrease of current at the beginnin...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(87)83315-5
更新日期:1987-01-01 00:00:00
abstract::The structural dynamics of bovine erythrocyte Cu, Zn superoxide dismutase (BSOD) was studied by time-resolved fluorescence spectroscopy. BSOD is a homodimer containing a single tyrosine residue (and no tryptophan) per subunit. Frequency-domain fluorometry revealed a heterogeneous fluorescence decay that could be descr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(94)80901-4
更新日期:1994-04-01 00:00:00
abstract::Loss of myelin in the central nervous system (CNS) leads to debilitating neurological deficits. High-resolution optical imaging of myelin in the CNS of animal models is limited by a lack of in vivo myelin labeling strategies. We demonstrated that third harmonic generation (THG) microscopy-a coherent, nonlinear, dye-fr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.01.031
更新日期:2011-03-02 00:00:00
abstract::The effects of cholesterol (Chol) on phospholipid bilayers include ordering of the fatty acyl chains, condensing of the lipids in the bilayer plane, and promotion of the liquid-ordered phase. These effects depend on the type of phospholipids in the bilayer and are determined by the nature of the underlying molecular i...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.088427
更新日期:2007-02-15 00:00:00
abstract::Estimates of the free myoplasmic [Ca2+] ([Ca2+]i) with fluorescent dyes are complicated by the fact that some properties of these dyes are altered in the intracellular environment. In the present study indo-1 was used to measure [Ca2+]i in isolated muscle fibers from Xenopus frogs. Fluorescent ratio signals obtained f...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79294-9
更新日期:1996-08-01 00:00:00
abstract::This paper describes a molecular dynamics and molecular mechanics study of the solvation and selectivity of the narrow pore and vestibule region of a model-built structure for the voltage-gated sodium channel. The particular structure used was one proposed by Guy and Durell. However, many of the features we saw would ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79438-9
更新日期:1996-11-01 00:00:00
abstract::In two-color fluorescence correlation spectroscopy (TCFCS), the fluorescence intensities of two fluorescently-labeled species are cross-correlated over time and can be used to identify static and dynamic interactions. Generally, fluorophore labels are chosen that do not undergo Förster resonance energy transfer (FRET)...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)75189-8
更新日期:2002-07-01 00:00:00
abstract::Although RNase Y acts as the key enzyme initiating messenger RNA decay in Bacillus subtilis and likely in many other Gram-positive bacteria, its three-dimensional structure remains unknown. An antibody belonging to the rare immunoglobulin G (IgG) 2b λx isotype was raised against a 12-residue conserved peptide from the...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2018.10.016
更新日期:2018-12-04 00:00:00