Abstract:
:The clustering of ryanodine receptors (RyR2) into functional Ca2+ release units is central to current models for cardiac excitation-contraction (E-C) coupling. Using immunolabeling and confocal microscopy, we have analyzed the distribution of RyR2 clusters in rat and ventricular atrial myocytes. The resolution of the three-dimensional structure was improved by a novel transverse sectioning method as well as digital deconvolution. In contrast to earlier reports, the mean RyR2 cluster transverse spacing was measured 1.05 microm in ventricular myocytes and estimated 0.97 microm in atrial myocytes. Intercalated RyR2 clusters were found interspersed between the Z-disks on the cell periphery but absent in the interior, forming double rows flanking the local Z-disks on the surface. The longitudinal spacing between the adjacent rows of RyR2 clusters on the Z-disks was measured to have a mean value of 1.87 microm in ventricular and 1.69 microm in atrial myocytes. The measured RyR2 cluster distribution is compatible with models of Ca2+ wave generation. The size of the typical RyR2 cluster was close to 250 nm, and this suggests that approximately 100 RyR2s might be present in a cluster. The importance of cluster size and three-dimensional spacing for current E-C coupling models is discussed.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Chen-Izu Y,McCulle SL,Ward CW,Soeller C,Allen BM,Rabang C,Cannell MB,Balke CW,Izu LTdoi
10.1529/biophysj.105.077180subject
Has Abstractpub_date
2006-07-01 00:00:00pages
1-13issue
1eissn
0006-3495issn
1542-0086pii
S0006-3495(06)71703-9journal_volume
91pub_type
杂志文章abstract::The coupling between the mechanical properties of enzymes and their biological activity is a well-established feature that has been the object of numerous experimental and theoretical works. In particular, recent experiments show that enzymatic function can be modulated anisotropically by mechanical stress. We study s...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.09.026
更新日期:2010-11-17 00:00:00
abstract::The proline-, glutamate-, valine-, and lysine-rich (PEVK) domain of the giant muscle protein titin is thought to be an intrinsically unstructured random-coil segment. Various observations suggest, however, that the domain may not be completely devoid of internal interactions and structural features. To test the validi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2012.08.042
更新日期:2012-10-03 00:00:00
abstract::The kinetics of porin incorporation into black lipid membranes (BLM) made of phosphatidylinositol (PI) or oxidized cholesterol (Ox Ch) were studied by means of alternating current; the set-up was able to acquire resistance and capacitance simultaneously by means of a mixed double-frequency approach at 1 Hz and 1 KHz, ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79283-4
更新日期:1996-08-01 00:00:00
abstract::The recent work is surveyed which leads to the suggestions that the conformation of globular proteins in solution corresponds to a dynamic ensemble of rapidly interconverting spatial structures, that clusters of hydrophobic amino acid side chains have an important role in the architecture of protein molecules, and tha...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(80)84989-7
更新日期:1980-10-01 00:00:00
abstract::Red blood cells (RBCs) have highly deformable viscoelastic membranes exhibiting complex rheological response and rich hydrodynamic behavior governed by special elastic and bending properties and by the external/internal fluid and membrane viscosities. We present a multiscale RBC model that is able to predict RBC mecha...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.02.002
更新日期:2010-05-19 00:00:00
abstract::The availability of very high magnetic fields of up to 170,000 gauss made it worthwhile to pursue the search for a critical change in the rate of four enzyme substrate reactions. The four enzymes were ribonuclease, polyphenol oxidase, peroxidase, and aldolase. The experiments showed that, to within +/-3%, no detectabl...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(67)86583-4
更新日期:1967-03-01 00:00:00
abstract::Aggregated Markov models are a widely used tool to model patch clamp data measured from single ion channels. These channels must obey the principle of detailed balance in thermodynamic equilibrium; otherwise, the channel is driven by an external source of energy. We investigate the power of a likelihood ratio test for...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76529-5
更新日期:2000-12-01 00:00:00
abstract::Microscopic calcium (Ca2+) events (such as Ca2+ sparks) are an important area for study, as they help clarify the mechanism(s) underlying intracellular signaling. In the heart, Ca2+ sparks occur as a result of Ca2+ release from the sarcoendoplasmic reticulum, via ryanodine receptor channels. Measurement of Ca2+ spark ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.135251
更新日期:2008-12-15 00:00:00
abstract::Over the last decade, functionally designed DNA nanostructures applied to lipid membranes prompted important achievements in the fields of biophysics and synthetic biology. Taking advantage of the universal rules for self-assembly of complementary oligonucleotides, DNA has proven to be an extremely versatile biocompat...
journal_title:Biophysical journal
pub_type: 杂志文章,评审
doi:10.1016/j.bpj.2016.03.015
更新日期:2016-04-26 00:00:00
abstract::The rotation of human red blood cells (RBC) as they flow in the shear field established by a Coulter type orifice is modeled. This model, based on hydrodynamics of ellipsoid rotation in laminar creeping flow, is used to calculate the probability of the cells entering the orifice with a specific orientation. The electr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(71)86204-5
更新日期:1971-02-01 00:00:00
abstract::Molecular dynamics simulations are performed on two hydrated dipalmitoylphosphatidylcholine bilayer systems: one with pure water and one with added NaCl. Due to the rugged nature of the membrane/electrolyte interface, ion binding to the membrane surface is characterized by the loss of ion hydration. Using this structu...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)75102-9
更新日期:2003-06-01 00:00:00
abstract::Molecular machines fueled by NTP play pivotal roles in a wide range of cellular activities. One common feature among NTP-driven molecular machines is that NTP binding is a major force-generating step among the elementary reaction steps comprising NTP hydrolysis. To understand the mechanism in detail,in this study, we ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.05.016
更新日期:2014-07-01 00:00:00
abstract::Thermotropic phase transitions in single planar bilayers of glycerol mono-oleate have been investigated using quasi-elastic light scattering from thermally excited membrane fluctuations. In certain cases both spectroscopic and intensity information were derived from the observations. For solvent-free bilayers transiti...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(86)83716-X
更新日期:1986-04-01 00:00:00
abstract::Formation of α-helices is a fundamental process in protein folding and assembly. By studying helix formation in molecular simulations of a series of alanine-based peptides, we obtain the temperature-dependent α-helix propensities of all 20 naturally occurring residues with two recent additive force fields, Amber ff03w...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2012.02.024
更新日期:2012-03-21 00:00:00
abstract::FKBP12 was removed from ryanodine receptors (RyRs) by incubation of rabbit skeletal muscle terminal cisternae membranes with rapamycin. The extent of FKBP12 removal was estimated by immunostaining Western blots of terminal cisternae proteins. Single FKBP12-depleted RyR channels, incorporated into planar lipid bilayers...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78654-5
更新日期:1997-01-01 00:00:00
abstract::Twenty-seven mutant bacteriorhodopsin's were screened to determine the PKa for reversal of the permanent electric dipole moment. The photoelectric response of an aqueous purple-membrane suspension was used to determine the direction of the purple-membrane dipole moment as a function of pH. The pK(a) for the dipole rev...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79802-8
更新日期:1996-05-01 00:00:00
abstract::The present article considers the influence of heterogeneity in a mobile analyte or in an immobilized ligand population on the surface binding kinetics and equilibrium isotherms. We describe strategies for solving the inverse problem of calculating two-dimensional distributions of rate and affinity constants from expe...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)75132-7
更新日期:2003-06-01 00:00:00
abstract::13C alpha chemical shifts and site-specific unfolding curves are reported for 12 sites on a 33-residue, GCN4-like leucine zipper peptide (GCN4-lzK), ranging over most of the chain and sampling most heptad positions. Data were derived from NMR spectra of nine synthetic, isosequential peptides bearing 99% 13C alpha at s...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78136-0
更新日期:1997-08-01 00:00:00
abstract::KL(4) is a 21-residue functional peptide mimic of lung surfactant protein B, an essential protein for lowering surface tension in the alveoli. Its ability to modify lipid properties and restore lung compliance was investigated with circular dichroism, differential scanning calorimetry, and solid-state NMR spectroscopy...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2008.12.3966
更新日期:2009-05-20 00:00:00
abstract::The relationship between epithelial fluid transport, standing osmotic gradients, and standing hydrostatic pressure gradients has been investigated using a perturbation expansion of the governing equations. The assumptions used in the expansion are: (a) the volume of lateral intercellular space per unit volume of epith...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(85)83986-2
更新日期:1985-06-01 00:00:00
abstract::At present, fluorescence recovery after photobleaching (FRAP) data are interpreted using various types of reaction-diffusion (RD) models: the model type is usually fixed first, and corresponding model parameters are inferred subsequently. In this article, we describe what we believe to be a novel approach for RD model...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.01.041
更新日期:2011-03-02 00:00:00
abstract::Recent development of titratable coions has paved the way for realizing all-atom molecular dynamics at constant pH. To further improve physical realism, here we describe a technique in which proton titration of the solute is directly coupled to the interconversion between water and hydroxide or hydronium. We test the ...
journal_title:Biophysical journal
pub_type: 信件
doi:10.1016/j.bpj.2013.06.036
更新日期:2013-08-20 00:00:00
abstract::Giant bilayer vesicles were reconstituted from several lipids and lipid/cholesterol (CHOL) mixtures: stearolyloleoylphosphatidylcholine (SOPC), bovine sphingomyelin (BSM), diarachidonylphosphatidylcholine (DAPC), SOPC/CHOL, BSM/CHOL, DAPC/CHOL, and extracted red blood cell (RBC) lipids with native cholesterol. Single-...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(90)82444-9
更新日期:1990-10-01 00:00:00
abstract::The cytoskeletal protein MreB is an essential component of the bacterial cell-shape generation system. Using a superresolution variant of total internal reflection microscopy with structured illumination, as well as three-dimensional stacks of deconvolved epifluorescence microscopy, we found that inside living Bacillu...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2013.07.038
更新日期:2013-09-03 00:00:00
abstract::We have obtained new insights into the behavior of a class of excitable systems when a stimulus, or parameter, is slowly tuned through a threshold value. Such systems do not accommodate no matter how slowly a stimulus ramp is applied, and the stimulus value at onset of repetitive activity shows a curious, nonmonotonic...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(88)82988-6
更新日期:1988-09-01 00:00:00
abstract::In vitro and in situ tests have been run to characterize the reaction of the mettalochromic indicator, arsenazo III, with calcium. Job plots as well as plots of indicator absorbance vs. [Ca2+] at different indicator concentrations show a 1:1 reaction stoichiometry. Equilibrium analysis and analysis using Adair's equat...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(80)85025-9
更新日期:1980-12-01 00:00:00
abstract::Total internal reflection excitation used in combination with fluorescence correlation spectroscopy (TIR-FCS) is a method for characterizing the dynamic behavior and absolute concentrations of fluorescent molecules near or at the interface of a planar substrate and a solution. In this work, we demonstrate for the firs...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74748-1
更新日期:2003-11-01 00:00:00
abstract::Diluted bull semen samples were bombarded with a 24 Mev proton beam. Dose response curves for the fraction of cells which survived the bombardment and for the average velocity of the surviving cells were measured. Target theory indicated a cross section of the sensitive volume of 2.1 x 10(-10) cm(2). Respiration measu...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(69)86421-0
更新日期:1969-06-01 00:00:00
abstract::Physical origin of DNA condensation by multivalent cations remains unsettled. Here, we report quantitative studies of how one DNA-condensing ion (Cobalt(3+) Hexammine, or Co(3+)Hex) and one nonDNA-condensing ion (Mg(2+)) compete within the interstitial space in spontaneously condensed DNA arrays. As the ion concentrat...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2013.07.004
更新日期:2013-08-20 00:00:00
abstract::Intracellular reactions are carried out in a crowded medium where the macromolecules occupy ∼40% of the total volume. This decrease in the available volume affects the activity of the reactants. Scaled particle theory is used for the estimation of the activity coefficients of the metabolites, and thereby for the asses...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2015.09.030
更新日期:2015-12-01 00:00:00