Abstract:
:Sedimentation velocity analytical ultracentrifugation is an important tool in the characterization of macromolecules and nanoparticles in solution. The sedimentation coefficient distribution c(s) of Lamm equation solutions is based on the approximation of a single, weight-average frictional coefficient of all particles, determined from the experimental data, which scales the diffusion coefficient to the sedimentation coefficient consistent with the traditional s approximately M(2/3) power law. It provides a high hydrodynamic resolution, where diffusional broadening of the sedimentation boundaries is deconvoluted from the sedimentation coefficient distribution. The approximation of a single weight-average frictional ratio is favored by several experimental factors, and usually gives good results for chemically not too dissimilar macromolecules, such as mixtures of folded proteins. In this communication, we examine an extension to a two-dimensional distribution of sedimentation coefficient and frictional ratio, c(s,f(r)), which is representative of a more general set of size-and-shape distributions, including mass-Stokes radius distributions, c(M,R(S)), and sedimentation coefficient-molar mass distributions c(s,M). We show that this can be used to determine average molar masses of macromolecules and characterize macromolecular distributions, without the approximation of any scaling relationship between hydrodynamic and thermodynamic parameters.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Brown PH,Schuck Pdoi
10.1529/biophysj.106.081372subject
Has Abstractpub_date
2006-06-15 00:00:00pages
4651-61issue
12eissn
0006-3495issn
1542-0086pii
S0006-3495(06)72640-6journal_volume
90pub_type
杂志文章abstract::We analyze a two-state stochastic corral model for regulation of protein diffusion in a cell membrane. This model could mimic control of protein transport in the membrane by the cytoskeleton. The dynamic corral acts as a gate which when open permits an otherwise trapped protein to escape to a neighboring corral in the...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76579-9
更新日期:2000-01-01 00:00:00
abstract::If a branched multistep editing mechanism is implemented by an enzyme with a single site for the specific substrates, there is no reason to believe that the number of testing steps is fixed and cannot be controlled by some external factors. The paper considers the mechanisms of single- or multistep editing done in res...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(82)84469-X
更新日期:1982-11-01 00:00:00
abstract::The earliest event in exocytosis is the formation of a fusion pore, an aqueous channel that connects the lumen of a secretory granule with the extracellular space. We can observe the formation of individual fusion pores and their subsequent dilation or closure by measuring the changes in the admittance of patch-clampe...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(92)81884-2
更新日期:1992-03-01 00:00:00
abstract::Given some simple kinetic models of the photocycle of bacteriorhodopsin (bR) and data taken at many wavelengths and under conditions that avoid photoselection and steady-state cycling complications, it is shown how to extract the apparent rate constants and the spectra of the intermediates. Special consideration was g...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(82)84543-8
更新日期:1982-05-01 00:00:00
abstract::Human immunodeficiency virus-1 viral infectivity factor (Vif) is an intrinsically disordered protein responsible for the ubiquitination of the APOBEC3 (A3) antiviral proteins. Vif folds when it binds Cullin-RING E3 ligase 5 and the transcription cofactor CBF-β. A five-protein complex containing the substrate receptor ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.03.014
更新日期:2019-04-23 00:00:00
abstract::We study the lateral headgroup interactions among phosphatidylcholine (PC) molecules and among phosphatidylethanolamine (PE) molecules in monolayers and extend our previous models. In this paper, we present an extensive set of pressure-area isotherms and surface potential experiments on monolayers of phospholipids ran...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(92)81964-1
更新日期:1992-06-01 00:00:00
abstract::The ejection of DNA from a bacterial virus (i.e., phage) into its host cell is a biologically important example of the translocation of a macromolecular chain along its length through a membrane. The simplest mechanism for this motion is diffusion, but in the case of phage ejection a significant driving force derives ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.070532
更新日期:2006-07-15 00:00:00
abstract::Steady-state polarization-resolved fluorescence imaging is used to analyze the molecular orientational order behavior of rigidly labeled major histocompatibility complex class I (MHC I) proteins and lipid probes in cell membranes of living cells. These fluorescent probes report the orientational properties of proteins...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.05.021
更新日期:2011-07-20 00:00:00
abstract::Erythrocytes were electrofused with multiple rectangular voltage pulses to show an oscillatory movement, divided into swell phases and pump events. During each swell phase, which lasted from 0.5 s to more than 180 s, the fused cells' (doublets') volume increased by colloid osmotic swelling, and the membrane area was e...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(99)77094-3
更新日期:1999-11-01 00:00:00
abstract::Finite difference solutions of the Poisson-Boltzmann equation are used to calculate the pKa values of the functionally important ionizable groups in bacteriorhodopsin. There are strong charge-charge interactions between the residues in the binding site leading to the possibility of complex titration behavior. Structur...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(94)80925-7
更新日期:1994-05-01 00:00:00
abstract::Nonphotochemical quenching is the protective mechanism against overexcitation of photosystem II, triggered by excess ΔpH in photosynthetic membranes. The light-harvesting complexes (LHCs), the de-epoxidation of violaxanthin to zeaxanthin, and the photosystem II subunit S (PsbS) work in synergy for an optimized multile...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.09.034
更新日期:2017-12-05 00:00:00
abstract::We introduce the use of microfabrication techniques to construct on a silicon wafer a synthetic capillary bed with 2.5- to 4-micron (mu)-wide channels. Establishment of a fluid pressure gradient allowed us to observe simultaneously using optical microscopy hundreds of cells flowing through the bed at physiological spe...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)80443-1
更新日期:1995-06-01 00:00:00
abstract::Benjamin Franklin, mostly known for his participation in writing The Declaration of Independence and work on electricity, was also one of the first scientists to seek to understand the properties of oil monolayers on water surfaces. During one of his many voyages across the Atlantic Ocean, Franklin observed that oil h...
journal_title:Biophysical journal
pub_type: 传,历史文章,杂志文章
doi:10.1016/j.bpj.2012.12.028
更新日期:2013-01-22 00:00:00
abstract::Specific amino acid sequence segments have been assigned to locations in the structural map of bacteriorhodopsin using two-dimensional neutron diffraction data and a model building analysis. Models are constructed computationally by building specific regions of the amino acid sequence as alpha helices and then positio...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(83)84391-4
更新日期:1983-06-01 00:00:00
abstract::Hemoglobin functions as a tetrameric oxygen transport protein, with each subunit containing a heme cofactor. Its denaturation, either in vivo or in vitro, involves autoxidation to methemoglobin, followed by cofactor loss and globin unfolding. We have proposed a global disassembly scheme for human methemoglobin, linkin...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2020.01.031
更新日期:2020-03-24 00:00:00
abstract::Far infrared (FIR) spectral measurements of wild-type (WT) and D96N mutant bacteriorhodopsin thin films have been carried out using terahertz time domain spectroscopy as a function of hydration, temperature, and conformational state. The results are compared to calculated spectra generated via normal mode analyses usi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74562-7
更新日期:2003-08-01 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::Fast Ca(2+) release kinetics were measured in cardiac sarcoplasmic reticulum vesicles actively loaded with Ca(2+). Release was induced in solutions containing 1.2 mM free ATP and variable free [Ca(2+)] and [Mg(2+)]. Release rate constants (k) were 10-fold higher at pCa 6 than at pCa 5 whereas Ryanodine binding was hig...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)75037-1
更新日期:2003-04-01 00:00:00
abstract::The application of a digital computer to the processing of data from single neurons is described. Examples from experimental data are presented to demonstrate the usefulness of certain types of computations. These methods are placed in a descriptive mathematical framework. Other easily attainable computations are sugg...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/s0006-3495(60)86872-5
更新日期:1960-09-01 00:00:00
abstract::A recently completed model of Ca concentration and movements in the cardiac cell diadic cleft space predicts that removal or neutralization of inner sarcolemmal (SL) leaflet anionic Ca-binding sites at the sarcolemmal border of this space will greatly diminish Na/Ca exchange-mediated Ca efflux. The present study tests...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79792-8
更新日期:1996-05-01 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::We modeled two different mechanisms, a shunting conductance and a slow sodium inactivation, to test whether they could modulate the active propagation of a train of action potentials in a dendritic tree. Computer simulations, using a compartmental model of a pyramidal neuron, suggest that each of these two mechanisms ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79433-X
更新日期:1996-11-01 00:00:00
abstract::The (31)P-nuclear magnetic resonance chemical shift of phosphatidic acid in a membrane is sensitive to the lipid head group packing and can report qualitatively on membrane lateral compression near the aqueous interface. We have used high-resolution (31)P-nuclear magnetic resonance to evaluate the lateral compression ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)73915-5
更新日期:2002-09-01 00:00:00
abstract::The mechanism of pH-triggered destabilization of liposomes composed of a polyethyleneglycol-orthoester-distearoylglycerol lipid (POD) and phosphatidyl ethanolamine (PE) has been studied using an ANTS/DPX leakage and a lipid-mixing assay. We developed a kinetic model that relates POD hydrolysis to liposome collapse. Th...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/s0006-3495(03)74986-8
更新日期:2003-03-01 00:00:00
abstract::The channels present on the surface membrane of isolated rat flexor digitorum brevis muscle fibers were surveyed using the patch clamp technique. 85 out of 139 fibers had a novel channel which excluded the anions chloride, sulfate, and isethionate with a permeability ratio of chloride to sodium of less than 0.05. The ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(91)82340-2
更新日期:1991-06-01 00:00:00
abstract::A new experimental approach has been developed to study the distribution of local electrostatic potential around specific protons in biologically important molecules. The approach is the development of a method denoted as "spin label/spin probe," which was proposed by one of us (. Mol. Biol. 6:498-507). The proposed m...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(99)76902-X
更新日期:1999-07-01 00:00:00
abstract::The addition of 10(-3) M p-chloromercuribenzene sulfonate (PCMBS) to the solution bathing the mucosal surface of rabbit colon has no effect on the rate of active Na transport but blocks or reverses the inhibitory action of amiloride. The tissue must be exposed to PCMBS for 20-30 min for a complete blocking effect, and...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(78)85477-0
更新日期:1978-04-01 00:00:00
abstract::Verapamil and amlodipine are calcium ion influx inhibitors of wide clinical use. They are partially charged at neutral pH and exhibit amphiphilic properties. The noncharged species can easily cross the lipid membrane. We have measured with solid-state NMR the structural changes induced by verapamil upon incorporation ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.089581
更新日期:2006-10-15 00:00:00
abstract::Slow stretch ramps (velocity: 0.17 fiber lengths s-1) were imposed during fused tetanic contractions of intact muscle fibers of the frog (1.4-3.0 degrees C; sarcomere length: 2.12-2.21 microns). Instantaneous force-extension relations were derived both under isometric conditions and during slow stretch by applying fas...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(89)82689-X
更新日期:1989-08-01 00:00:00
abstract::A detailed experimental description of molecular dynamics requires an accurate description of the global correlation time. For the gramicidin cation-selective channel the local dynamics of the polypeptide backbone are thought to play a very significant role in the functional process of this channel which occurs on the...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(93)81150-0
更新日期:1993-09-01 00:00:00