Abstract：
:Using both analytical solutions obtained from simplified systems and numerical results from more realistic cases, we investigate the role played by the dielectric constant of membrane proteins epsilon(p) and pore water epsilon(w) in permeation of ions across channels. We show that the boundary and its curvature are the crucial factors in determining how an ion's potential energy depends on the dielectric constants near an interface. The potential energy of an ion outside a globular protein has a dominant 1/epsilon(w) dependence, but this becomes 1/epsilon(p) for an ion inside a cavity. For channels, where the boundaries are in between these two extremes, the situation is more complex. In general, we find that variations in epsilon(w) have a much larger impact on the potential energy of an ion compared to those in epsilon(p). Therefore a better understanding of the effective epsilon(w) values employed in channel models is desirable. Although the precise value of epsilon(p) is not a crucial determinant of ion permeation properties, it still needs to be chosen carefully when quantitative comparisons with data are made.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Baştuğ T,Kuyucak Sdoi
10.1016/S0006-3495(03)70015-0subject
Has Abstractpub_date
2003-05-01 00:00:00pages
2871-82issue
5eissn
0006-3495issn
1542-0086pii
S0006-3495(03)70015-0journal_volume
84pub_type
杂志文章abstract：:This work presents a methodology to measure and quantitatively interpret force curves on supported lipid bilayers in water. We then use this method to correlate topographic imaging contrast in atomic force microscopy (AFM) images of phase-separated Langmuir-Blodgett bilayers with imaging load. Force curves collected o...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(00)76364-8
更新日期：2000-08-01 00:00:00
abstract：:The continuum and single jump treatments of ion transport through black lipid membranes predict experimentally distinguishable results, even when the same mechanistic assumptions are made and the same potential-distance profile is used. On the basis of steady-state current-voltage curves for nonactin-mediated transpor...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(85)83766-8
更新日期：1985-07-01 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：:It is well known that the dsDNA molecule undergoes a phase transition from B-DNA into an overstretched state at high forces. For some time, the structure of the overstretched state remained unknown and highly debated, but recent advances in experimental techniques have presented evidence of more than one possible phas...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2014.09.014
更新日期：2014-11-04 00:00:00
abstract：:Biochemical systems lose their homogeneity at a mesoscopic scale; physical parameters vary sharply over a scale of a few nanometers.In this manuscript, we demonstrate how proton diffusion studies can report the microscopic properties of inhomogeneous systems.The method used for this purpose was the laser induced proto...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(92)81584-9
更新日期：1992-07-01 00:00:00
abstract：:A number of important pluripotency regulators, including the transcription factor Nanog, are observed to fluctuate stochastically in individual embryonic stem cells. By transiently priming cells for commitment to different lineages, these fluctuations are thought to be important to the maintenance of, and exit from, p...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2017.05.005
更新日期：2017-06-20 00:00:00
abstract：:Intrinsic optical signal (IOS) imaging has been widely used to map the patterns of brain activity in vivo in a label-free manner. Traditional IOS refers to changes in light transmission, absorption, reflectance, and scattering of the brain tissue. Here, we use polarized light for IOS imaging to monitor structural chan...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2020.03.016
更新日期：2020-05-19 00:00:00
abstract：:The enzyme F1-adenosine triphosphatase (ATPase) is a molecular motor that converts the chemical energy stored in the molecule adenosine triphosphate (ATP) into mechanical rotation of its gamma-subunit. During steady-state catalysis, the three catalytic sites of F1 operate in a cooperative fashion such that at every in...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1529/biophysj.104.046128
更新日期：2004-11-01 00:00:00
abstract：:Mechanosensitive ion channels (MSCs) which could provide for fast osmoregulatory responses in bacteria, remain unidentified as molecular entities. MSCs from Escherichia coli (strain AW740) were examined using the patch-clamp technique, either (a) in giant spheroplasts, (b) after reconstitution by fusing native membran...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(93)81044-0
更新日期：1993-07-01 00:00:00
abstract：:Chemical synaptic transmission is a fundamental component of interneuronal communications in the central nervous system (CNS). Discharge of a presynaptic vesicle containing a few thousand molecules (a quantum) of neurotransmitter into the synaptic cleft generates a transmitter concentration signal that drives postsyna...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(97)78761-7
更新日期：1997-03-01 00:00:00
abstract：:Current methods for analysis of data from studies of protein-protein interactions using fluorescence resonance energy transfer (FRET) emerged from several decades of research using wide-field microscopes and spectrofluorometers to measure fluorescence from individual cells or cell populations. Inherent to most measure...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2010.01.048
更新日期：2010-05-19 00:00:00
abstract：:The increasingly widespread use of parametric mathematical models to describe biological systems means that the ability to infer model parameters is of great importance. In this study, we consider parameter inferability in nonlinear ordinary differential equation models that undergo a bifurcation, focusing on a simple...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1529/biophysj.107.126086
更新日期：2008-07-01 00:00:00
abstract：:The S4 transmembrane domain of the family of voltage-gated ion channels is generally thought to be the voltage sensor, whose translocation by an applied electric field produces the gating current. Experiments on hSkMI Na(+) channels and both Shaker and EAG K(+) channels indicate which S4 residues cross the membrane-so...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(03)74708-0
更新日期：2003-11-01 00:00:00
abstract：:The bile acid-sensitive ion channel is activated by amphiphilic substances such as bile acids or artificial detergents via membrane alterations; however, the mechanism of membrane sensitivity of the bile acid-sensitive ion channel is not known. It has also not been systematically investigated whether other members of ...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2018.01.028
更新日期：2018-03-27 00:00:00
abstract：:The information theory measure of transfer entropy is used to extract the causality of correlated motions from molecular dynamics simulations. For each pair of correlated residues, the method quantifies which residue drives the correlated motions, and which residue responds. The measure reveals how correlated motions ...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2009.07.019
更新日期：2009-09-16 00:00:00
abstract：:The average sizes of fluid and gel domains in the two-component, two-phase system formed from mixtures of dimyristoyl phosphatidylcholine and distearoyl phosphatidylcholine were determined from an analysis of the electron spin resonance spectral lineshapes of a dimyristoyl phosphatidylcholine-nitroxide spin label as a...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(92)81619-3
更新日期：1992-08-01 00:00:00
abstract：:Plant light-harvesting complex II (LHCII) is the key antenna complex for plant photosynthesis. We present coarse-grained molecular dynamics simulations of monomeric and trimeric LHCII in a realistic thylakoid membrane environment based on the Martini force field. The coarse-grained protein model has been optimized wit...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2019.03.009
更新日期：2019-04-23 00:00:00
abstract：:Stabilization of the lipid bilayer membrane in red blood cells by its association with an underlying membrane-associated cytoskeleton has long been recognized as critical for proper red blood cell function. One of the principal connections between skeleton and bilayer is via linkages between band 3, the integral membr...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1529/biophysj.108.129163
更新日期：2008-08-01 00:00:00
abstract：:Equations are derived describing the dispersion of a permeable solute during Poiseuille flow in a capillary model. It is shown that for the normal range of physiological parameters such as capillary radius, capillary length, blood flow, permeability coefficients, and diffusion constants, the center of mass of a bolus ...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(66)86637-7
更新日期：1966-01-01 00:00:00
abstract：:High-affinity and cooperative binding of two Ca(2+) per ATPase (SERCA) occurs within the membrane-bound region of the enzyme. Direct measurements of binding at various Ca(2+) concentrations demonstrate that site-directed mutations within this region interfere selectively with Ca(2+) occupancy of either one or both bin...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(02)75247-8
更新日期：2002-11-01 00:00:00
abstract：:The properties of vesicle membranes prepared from 16:0-SM, 16:0-DHSM, or DPPC were characterized using steady-state and time-resolved fluorescence spectroscopy and different fluorescent reporter molecules. The acyl-chain region was probed using free and phospholipid-bound 1,6-diphenyl-1,3,5-hexatriene. 16:0-DHSM was f...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(03)74915-7
更新日期：2003-02-01 00:00:00
abstract：:K(ATP) channels are comprised of a pore-forming protein, Kir6.x, and the sulfonylurea receptor, SURx. Interaction of adenine nucleotides with Kir6.2 positively charged amino acids such as K185 and R201 on the C-terminus causes channel closure. Substitution of these amino acids with other positively charged residues ha...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(03)74847-4
更新日期：2003-01-01 00:00:00
abstract：:It has long been appreciated that spatiotemporal dynamics of cell migration are under the control of intracellular signaling pathways, which are mediated by adhesion receptors and other transducers of extracellular cues. Further, there is ample evidence that aspects of cell migration are stochastic: how else could it ...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2009.09.051
更新日期：2010-01-06 00:00:00
abstract：:The ryanodine receptor (RyR) of skeletal muscle contains two functional domains: a carboxyl-terminal hydrophobic domain that forms the putative conduction pore of the calcium release channel, and a large cytoplasmic domain that corresponds to the "foot structure." To understand the contribution of the foot structure t...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(97)78165-7
更新日期：1997-09-01 00:00:00
abstract：:The functions and elasticities of the cell are largely related to the structures of the cytoskeletons underlying the lipid bilayer. Among various cell types, the red blood cell (RBC) possesses a relatively simple cytoskeletal structure. Underneath the membrane, the RBC cytoskeleton takes the form of a two-dimensional ...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2015.10.036
更新日期：2015-12-01 00:00:00
abstract：:A major component of green tea extracts, catechin (-)-Epigallocatechin gallate (EGCg), has been reported to be biologically active and interacting with membranes. A recent study reported drastic effects of EGCg on giant unilamellar vesicles (GUVs). In particular, EGCg above 30 microM caused GUVs to burst. Here we inve...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2008.11.007
更新日期：2009-02-01 00:00:00
abstract：:A new flow configuration allows a flow cytometer of high resolution and stability to be assembled from an inverted fluorescence microscope with incident illumination, a pulse photometer, and a multichannel pulse height analyzer. A nozzle produces a hydrodynamically focused sample stream in a liquid jet that id directe...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(79)85157-7
更新日期：1979-10-01 00:00:00
abstract：:Charge movement currents (IQ) and calcium transients (delta[Ca2+]) were measured simultaneously in frog skeletal muscle fibers, voltage clamped in a double vaseline gap chamber, using Antipyrylazo III as the calcium indicator. The rate of release of calcium from the SR (Rrel) was calculated from the calcium transients...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(92)81920-3
更新日期：1992-05-01 00:00:00
abstract：:The organization of the normal collagen molecule and fibrils is reviewed and the detection, assay, and isolation of a collagenolytic enzyme from amphibian tadpole tissue are described and its possible significance in metamorphosis is discussed ...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/s0006-3495(64)86928-9
更新日期：1964-01-01 00:00:00
abstract：:Variation in the amplitude of miniature postsynaptic currents (mPSCs) generated by individual quanta of neurotransmitter is a major contributor to the variance of evoked synaptic responses. Here we explore the possible origins of this variability by developing a mathematical description of mPSC generation and consider...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(96)79325-6
更新日期：1996-09-01 00:00:00
