Abstract:
:The interaction between actin and myosin in the filament array of glycerinated muscle fibers has been monitored using paramagnetic probes and mechanical measurements. Both fiber stiffness and the spectra of probes bound to a reactive sulfydral on the myosin head were measured as the actomyosin bond was weakened by addition of magnesium pyrophosphate (MgPPi) and glycerol. In the absence of MgPPi, all myosin heads are attached to actin with oriented probes. When fibers were incubated in buffers containing MgPPi, a fraction of the probes became disordered, and this effect was greater in the presence of glycerol. To determine whether the heads with disordered probes were detached from actin, spin-labeled myosin subfragment-1 (MSL-S1) was diffused into unlabeled fibers, and the fractions bound to actin and free in the medium were correlated with the oriented and disordered spectral components. These experiments showed that the label was oriented when MSL-S1 was attached to actin in a ternary complex with the ligand and that all heads with disordered probes were detached from actin. Thus the fraction of oriented labels could be used to determine the fraction of heads attached to actin in a fiber in the presence of ligand. The fraction of myosin heads attached to actin decreased with increasing [MgPPi], and in the absence of glycerol approximately 50% of the myosin heads were dissociated at 3.3 mM ligand with little change in fiber stiffness. In the presence of 37% glycerol plus ligand, up to 80% of the heads could be detached with a 50% decrease in fiber stiffness. The data indicate that there are two populations of myosin heads in the fiber. All the data could be fit with a model in which one population of myosin heads (comprising approximately 50% of the total) sees an apparent actin concentration of 0.1 mM and can be released from actin with little change in fiber stiffness. A second population of myosin heads (approximately 50%) sees a higher actin concentration (5 mM) and is only released in the presence of both glycerol and ligand.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Pate E,Cooke Rdoi
10.1016/S0006-3495(88)83136-9subject
Has Abstractpub_date
1988-04-01 00:00:00pages
561-73issue
4eissn
0006-3495issn
1542-0086pii
S0006-3495(88)83136-9journal_volume
53pub_type
杂志文章abstract::Current viral docking models have relied upon the assumption that bond formation and breakage are independent of viral and docking surface geometry, as well as the forces exerted on the bonds. This assumption, known as the equivalent site hypothesis (ESH), is examined in detail using a newly developed simulation techn...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.103.027813
更新日期:2004-06-01 00:00:00
abstract::In a relaxed muscle fiber at low ionic strength, the cross-bridges may well be in states comparable to the one that precedes the cross-bridge power stroke (Schoenberg, M. 1988. Adv. Exp. Med. Biol. 226:189-202). Using electron paramagnetic resonance (EPR) and (saturation transfer) electron paramagnetic resonance (ST-E...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(91)82093-8
更新日期:1991-09-01 00:00:00
abstract::Nef is an HIV-1 accessory protein that directly contributes to AIDS progression. Nef is myristoylated on the N-terminus, associates with membranes, and may undergo a transition from a solution conformation to a membrane-associated conformation. It has been hypothesized that conformational rearrangement enables membran...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.07.016
更新日期:2010-09-22 00:00:00
abstract::Studies have been performed on erythrocytes that have been subjected to a low shear stress of less than 100 dyn/cm(2) in a cone-and-plate viscometer. Alterations that were observed included decreased red cell survival, increased osmotic fragility, changes in the cation permeability of the red cell membrane, and a redu...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(73)86056-4
更新日期:1973-11-01 00:00:00
abstract::Differential scanning calorimetry provides a new window into the plasma proteome. Plasma from normal individuals yields a characteristic, reproducible thermogram that appears to represent the weighted sum of denaturation profiles of the most abundant constituent plasma proteins. Plasma from diseased individuals yields...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.119453
更新日期:2008-02-15 00:00:00
abstract::We study a differential equation that models nerve impulse transmission. The nonlinearity is simplified to be piecewise linear in order to allow explicit solution. In general, two solitary impulse solutions are exhibited. The temporal stability of these solutions is analyzed by a technique that identifies the number o...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(78)85511-8
更新日期:1978-02-01 00:00:00
abstract::Spontaneous conversion of beta-amyloid peptide (Abeta) from soluble monomer to insoluble fibril may underlie the neurodegeneration associated with Alzheimer's disease. A complete description of Abeta self-association kinetics requires identification of the oligomeric species present and the pathway of association, as ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)75831-6
更新日期:2001-09-01 00:00:00
abstract::The rat connexin40 gap junction channel is permeable to monovalent cations including tetramethylammonium and tetraethylammonium ions. Larger tetraalkyammonium (TAA(+)) ions beginning with tetrabutylammonium (TBA(+)) reduced KCl junctional currents disproportionately. Ionic blockade by tetrapentylammonium (TPeA(+)) and...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)75960-7
更新日期:2001-12-01 00:00:00
abstract::The separation method, flow field-flow fractionation (flow FFF), is coupled on-line with multiangle laser light scattering (MALLS) for simultaneous measurement of the size and concentration of vesicles eluting continuously from the fractionator. These size and concentration data, gathered as a function of elution time...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(98)78033-6
更新日期:1998-06-01 00:00:00
abstract::Internally perfused squid giant axons with intact sodium inactivation gating were prepared for gating current experiments. Gating current records were obtained in sinusoidally driven dynamic steady states and as dynamic transients as functions of the mean membrane potential and the frequency of the command sinusoid. C...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(86)83486-5
更新日期:1986-09-01 00:00:00
abstract::Antibodies are key tools in biomedical research and medicine. Their binding properties are classically measured in solution and characterized by an affinity. However, in physiological conditions, antibodies can bridge an immune effector cell and an antigen-presenting cell, implying that mechanical forces may apply to ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.03.012
更新日期:2019-04-23 00:00:00
abstract::The mitochondrial channel, VDAC, forms large (3 nm in diameter) aqueous pores through membranes. We measured ATP flow (using the luciferin/luciferase method) through these channels after reconstitution into planar phospholipid membranes. In the open state of VDAC, as many as 2 x 10(6) ATP molecules can flow through on...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78841-6
更新日期:1997-05-01 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
abstract::Three features appear to characterize steady-state light adaptation in vertebrate cone photoreceptors: (a) the shape of the "log intensity-response" curve at different levels of adaptation is the same, the only change with adaptation is in the position of the point on the curve about which the cones operate; (b) at hi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(82)84502-5
更新日期:1982-08-01 00:00:00
abstract::We have used admittance analysis together with the black lipid membrane technique to analyze electrogenic reactions within the Na(+) branch of the reaction cycle of the Na(+)/K(+)-ATPase. ATP release by flash photolysis of caged ATP induced changes in the admittance of the compound membrane system that are associated ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76496-4
更新日期:2000-11-01 00:00:00
abstract::Values of K, delta G(o), delta H(o), delta S(o) and delta C(po) for the binding reaction of small organic ligands forming 1:1 complexes with either alpha- or beta-cyclodextrin were obtained by titration calorimetry from 15 degrees C to 45 degrees C. A hydrogen bond or hydrophobic interaction was introduced by adding a...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79415-8
更新日期:1996-10-01 00:00:00
abstract::Gramicidin is a polypeptide antibiotic that forms monovalent cation-specific channels in membrane environments. In organic solvents and in lipids containing unsaturated fatty acid chains, it forms a double-helical "pore" structure, in which two monomers are intertwined. This form of gramicidin can bind two cations ins...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79213-5
更新日期:1996-07-01 00:00:00
abstract::A refined mesoscopic model for the cumulative effect of repulsive excluded volume protein-protein interaction and attractive protein-surface interaction upon the properties of a trace protein capable of fiber formation is presented. The model predicts that very small changes in the magnitude of bulk volume occupancy o...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.09.033
更新日期:2019-11-05 00:00:00
abstract::The thermal transitions of fibrillar collagen are investigated with second-harmonic generation polarization anisotropy microscopy. Second-harmonic generation images and polarization anisotropy profiles of corneal stroma heated in the 35-80°C range are analyzed by means of a theoretical model that is suitable to probe ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2012.07.055
更新日期:2012-09-19 00:00:00
abstract::To understand the thermodynamic exclusion of Na(+) relative to K(+) from the S(2) site of the selectivity filter, the distribution P(X)(epsilon) (X = K(+) or Na(+)) of the binding energy (epsilon) of the ion with the channel is analyzed using the potential distribution theorem. By expressing the excess chemical potent...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2008.12.3917
更新日期:2009-03-18 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::The Ciona intestinalis voltage-sensitive phosphatase (Ci-VSP) represents the first discovered member of enzymes regulated by a voltage-sensor domain (VSD) related to the VSD found in voltage-gated ion channels. Although the VSD operation in Ci-VSP exhibits original voltage dependence and kinetics compared to ion chann...
journal_title:Biophysical journal
pub_type: 信件
doi:10.1016/j.bpj.2012.06.030
更新日期:2012-08-08 00:00:00
abstract::The effects of intracellular magnesium ions and extracellular calcium and magnesium ions on the delayed rectifier potassium ion channel, IK, were investigated from intracellularly perfused squid giant axons. Cao+2 and Mgo+2 both blocked IK in a voltage-independent manner with a KD of approximately 100 and 500 mM, resp...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)80047-0
更新日期:1995-11-01 00:00:00
abstract::Membrane nanotubes, also known as membrane tethers, play important functional roles in many cellular processes, such as trafficking and signaling. Although considerable progresses have been made in understanding the physics regulating the mechanical behaviors of individual membrane nanotubes, relatively little is know...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.01.032
更新日期:2019-03-05 00:00:00
abstract::We present a method for calculating the configurational-dependent diffusion coefficient of a globular protein as a function of the global folding process. Using a coarse-grained structure-based model, we determined the diffusion coefficient, in reaction coordinate space, as a function of the fraction of native contact...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.04.041
更新日期:2010-07-21 00:00:00
abstract::Adsorption of lambda-phage on sensitive bacteria Escherichia coli is a classical problem but not all issues have been resolved. One of the outstanding problems is the rate of adsorption, which in some cases appears to exceed the theoretical limit imposed by the law of random diffusion. We revisit this problem by condu...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.102962
更新日期:2007-07-01 00:00:00
abstract::Hepatitis C is a major worldwide disease and health hazard, affecting ∼3% of the world population. The p7 protein of hepatitis C virus (HCV) is an intracellular ion channel and pH regulator that is involved in the viral replication cycle. It is targeted by various classical ion channel blockers. Here, we generated p7 ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2016.04.018
更新日期:2016-06-07 00:00:00
abstract::Thermal inactivation of T(4) and lambda bacteriophage shows two components of differing sensitivity are present. These cannot be interpreted as owing to nucleic acid and protein. One protein function-the inhibition of radiation-induced DNA degradation-is lost with quite different thermal kinetics. lambda heated in the...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(71)86195-7
更新日期:1971-01-01 00:00:00
abstract::One of the unusual properties of elastin is its ability to coacervate, which has been proposed to play an important role in the alignment of monomeric elastin for cross-linking into the polymeric elastin matrix. The temperature at which this transition takes place depends on several factors including protein concentra...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.110809
更新日期:2007-11-15 00:00:00
abstract::Sister chromatids are topologically intertwined at the onset of anaphase: their segregation during anaphase is known to require strand-passing activity by type II DNA topoisomerase. We propose that the removal of the intertwinings involves at the same time the traction of the mitotic spindle and the activity of topois...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)80032-9
更新日期:1995-10-01 00:00:00