Abstract:
:The partial specific volume and adiabatic compressibility of proteins reflect the hydration properties of the solvent-exposed protein surface, as well as changes in conformational states. Reverse micelles, or water-in-oil microemulsions, are protein-sized, optically-clear microassemblies in which hydration can be experimentally controlled. We explore, by densimetry and ultrasound velocimetry, three basic proteins: cytochrome c, lysozyme, and myelin basic protein in reverse micelles made of sodium bis (2-ethylhexyl) sulfosuccinate, water, and isooctane and in aqueous solvents. For comparison, we use beta-lactoglobulin (pI = 5.1) as a reference protein. We examine the partial specific volume and adiabatic compressibility of the proteins at increasing levels of micellar hydration. For the lowest water content compatible with complete solubilization, all proteins display their highest compressibility values, independent of their amino acid sequence and charge. These values lie within the range of empirical intrinsic protein compressibility estimates. In addition, we obtain volumetric data for the transition of myelin basic protein from its initially unfolded state in water free of denaturants, to a folded, compact conformation within the water-controlled microenvironment of reverse micelles. These results disclose yet another aspect of the protein structural properties observed in membrane-mimetic molecular assemblies.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Valdez D,Le Huérou JY,Gindre M,Urbach W,Waks Mdoi
10.1016/S0006-3495(01)76243-1subject
Has Abstractpub_date
2001-06-01 00:00:00pages
2751-60issue
6eissn
0006-3495issn
1542-0086pii
S0006-3495(01)76243-1journal_volume
80pub_type
杂志文章abstract::We measured the exocytotic response induced by flash photolysis of caged compounds in isolated mast cells and chromaffin cells. Vesicle fusion was measured by monitoring the cell membrane capacitance. The release of vesicular contents was followed by amperometry. In response to a GTP gamma S stimulus we found that the...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79315-3
更新日期:1996-08-01 00:00:00
abstract::To explain the effect of profilin on actin critical concentration in a manner consistent with thermodynamic constraints and available experimental data, we built a thermodynamically rigorous model of actin steady-state dynamics in the presence of profilin. We analyzed previously published mechanisms theoretically and ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.134569
更新日期:2008-12-15 00:00:00
abstract::The fusion peptides of HIV and influenza virus are crucial for viral entry into a host cell. We report the membrane-perturbing and structural properties of fusion peptides from the HA fusion protein of influenza virus and the gp41 fusion protein of HIV. Our goals were to determine: 1), how fusion peptides alter struct...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.063032
更新日期:2005-11-01 00:00:00
abstract::The difference in the surface charge distribution between light-adapted and dark-adapted purple membranes was investigated with electric dichroism measurements from approximately pH 5 to pH 11. Purple membrane sheets in solution are oriented in a weak electric field by their permanent dipole moment, which is due to th...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(86)83454-3
更新日期:1986-08-01 00:00:00
abstract::NMR and CD studies have been used to analyze the model membrane-bound structure of the neuropeptide substance P (RPKPQQFFGLM-NH2, SP), which has previously been proposed as the NK1 receptor active form. Conformations were determined for the SP in the presence of aqueous solutions of zwitterionic dodecylphosphocholine ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79734-5
更新日期:1996-04-01 00:00:00
abstract::Previously (Hines, M., and J.J. Blum 1983, Biophys. J., 41:67-79), a method was developed that allowed one to compute curvature and twist for a three-dimensional sliding filament model. In that formalism it was difficult to specify the shear and bending moments arising from moment-bearing interfilament links such as f...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(84)84054-0
更新日期:1984-11-01 00:00:00
abstract::Two rate-limiting mechanisms have been proposed to explain the gramicidin channel facilitated decay of the pH difference across vesicular membrane (delta pH) in the pH region 6-8 and salt (MCI, M+ = K+, Na+) concentration range 50-300 mM. 1) At low pH conditions (approximately 6), H+ transport through the gramicidin c...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79503-6
更新日期:1996-12-01 00:00:00
abstract::We present a theoretical analysis of intracellular calcium waves propagated by calcium feedback at the inositol 1,4,5-trisphosphate (IP3) receptor. The model includes essential features of calcium excitability, but is still analytically tractable. Formulas are derived for the wave speed, amplitude, and width. The calc...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78888-X
更新日期:1997-06-01 00:00:00
abstract::Transport of large proteins into the nucleus involves two events, binding of the cargo protein to a transport receptor in the cytoplasm and passage of the cargo-transporter complex through the selective permeability barrier of the nuclear pore complex. The permeability barrier is formed by largely disordered polypepti...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.02.049
更新日期:2010-06-02 00:00:00
abstract::Determining the spatial relationship of individual proteins in dense assemblies remains a challenge for superresolution nanoscopy. The organization of aquaporin-4 (AQP4) into large plasma membrane assemblies provides an opportunity to image membrane-bound AQP4 antibodies (AQP4-IgG) and evaluate changes in their spatia...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.03.012
更新日期:2017-04-25 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::Phosphorescence spectroscopy on mouse myeloma IgA J539 in rigid solution at 77K revealed the type of anomalous short-lived component in the tryptophan decay originally observed with lysozyme (Churchich, J.E., 1966. Biochim. Biophys. Acta. 120:406-412) and seen in a large number of Bence Jones proteins (Longworth, J.W....
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(89)82681-5
更新日期:1989-08-01 00:00:00
abstract::It has been a long belief that release of substances from the cell to the extracellular milieu by exocytosis is completed by diffusion of the substances from secretory vesicles through the fusion pore. Involvement of any mechanical force that may be superposed on the diffusion to enhance the releasing process has not ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)75159-X
更新日期:2002-07-01 00:00:00
abstract::Neal and Cunningham (Neal, M. J., and J. R. Cunningham. 1995. J. Physiol. (Lond.). 482:363-372) showed that GABA(B) agonists and glycinergic antagonists enhance the light-evoked release of retinal acetylcholine. They proposed that glycinergic cells inhibit the cholinergic Starburst amacrine cells and are in turn inhib...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.072256
更新日期:2006-07-15 00:00:00
abstract::The conformation of mononucleosome complexes reconstituted with recombinant core histones on a 614-basepair-long DNA fragment containing the Xenopus borealis 5S rRNA nucleosome positioning sequence was studied by scanning/atomic force microscopy in the absence or presence of linker histone H1. Imaging without prior fi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74815-2
更新日期:2003-12-01 00:00:00
abstract::Cell migration is based on an actin treadmill, which in turn depends on recycling of G-actin across the cell, from the rear where F-actin disassembles, to the front, where F-actin polymerizes. To analyze the rates of the actin transport, we used the Virtual Cell software to solve the diffusion-drift-reaction equations...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.130096
更新日期:2008-08-01 00:00:00
abstract::Amyloid fibrils are associated with many neurodegenerative diseases. It was found that amyloidogenic oligomers, not mature fibrils, are neurotoxic agents related to these diseases. Molecular mechanisms of infectivity, pathways of aggregation, and molecular structure of these oligomers remain elusive. Here, we use all-...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2009.09.062
更新日期:2010-01-20 00:00:00
abstract::The geminate recombination kinetics of CO-myoglobin strongly deviates from single exponential behavior in contrast to what is expected for unimolecular reactions (1). At low temperatures, this result was attributed to slowly exchanging conformational states which differ substantially in barrier height for ligand bindi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(93)81554-6
更新日期:1993-06-01 00:00:00
abstract::To investigate diffusion processes in agarose gel, nanoparticles with sizes in the range between 1 and 140 nm have been tested by means of fluorescence correlation spectroscopy. Understanding the diffusion properties in agarose gels is interesting, because such gels are good models for microbial biofilms and cells cyt...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(04)74325-8
更新日期:2004-05-01 00:00:00
abstract::We expressed rod-type homotetrameric cyclic nucleotide-gated (CNGA1) channels in Xenopus oocytes and studied activation by photolysis-induced jumps of the 3',5'-cyclic guanosine monophosphate (cGMP) concentration and by voltage steps. cGMP jumps to increasing concentrations up to the EC50 value of 46.5 microM decelera...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.078667
更新日期:2006-05-01 00:00:00
abstract::Various differential polarization images or Mueller images of model objects are generated using the equations derived in the previous paper (paper I of this series). These calculated images include models of the higher-order organization of metaphase chromosomes, and show the applicability of the differential polariza...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(87)83286-1
更新日期:1987-12-01 00:00:00
abstract::Cholesterol is an essential molecule in the membranes of mammalian cells. It is known to be distributed heterogeneously within the cells, between the bilayer leaflets, as well as between lateral domains within the bilayer. However, we do not know exactly how cholesterol is distributed and what forces drive this sortin...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2018.11.3135
更新日期:2019-01-22 00:00:00
abstract::This paper is concerned with the nature of the transmembrane potential induced in an inactive nerve fiber lying in an impressed potential field within a nerve trunk. The impressed potential field is assumed to be produced by the synchronous activity of other fibers within the trunk; an expression for the induced trans...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(71)86214-8
更新日期:1971-03-01 00:00:00
abstract::An approach is introduced to characterize conformational ensembles of intrinsically unstructured peptides on the atomic level using two-dimensional solid-state NMR data and their combination with molecular dynamics simulations. For neurotensin, a peptide that binds with high affinity to a G-protein coupled receptor, t...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.059964
更新日期:2005-09-01 00:00:00
abstract::A phospholipid chelate complexed with ytterbium (DMPE-DTPA:Yb3+) is shown to be readily incorporated into a model membrane system, which may then be aligned in a magnetic field such that the average bilayer normal lies along the field. This so-called positively ordered smectic phase, whose lipids consist of less than ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(98)77659-3
更新日期:1998-11-01 00:00:00
abstract::It is shown that if x(t) is the solution of a second order differential equation, with real negative characteristic roots (not necessarily distinct), which exhibits an extremum at t = T, then T|x(T)|/|A| [UNK] 1/e where A is the area under the x(t) curve. This result is compared to a special case previously derived by...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/s0006-3495(61)86910-5
更新日期:1961-09-01 00:00:00
abstract::A variety of experiments suggest that membrane proteins are important targets of anesthetic molecules, and that ion channels interact differently with anesthetics in their open and closed conformations. The availability of an open and a closed structural model for the KirBac1.1 potassium channel has made it possible t...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.119958
更新日期:2008-06-01 00:00:00
abstract::Immunocytochemical, biochemical, and molecular genetic studies indicate that apolipoprotein E (apoE) plays an important role in the process of amyloidogenesis-beta. However, there is still no clear translation of these data into the pathogenesis of amyloidosis-beta. Previous studies demonstrated sodium dodecyl sulfate...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76354-5
更新日期:2000-08-01 00:00:00
abstract::A recent thermodynamic model describes a reversible reaction between cholesterol (C) and phospholipid (P) to form a condensed complex C(nq)P(np). Here q and p are relatively prime integers used to define the stoichiometric composition, and n is a measure of cooperativity. The present study applies this model to the sc...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)75920-6
更新日期:2001-11-01 00:00:00
abstract::To determine the effect of hydration on the dynamics of a protein complex, we used deuterium nuclear magnetic resonance (NMR) techniques to examine a trimethoprim (TMP)/E. coli dihydrofolate reductase (DHFR) complex in its lyophilized, partially hydrated, polycrystalline, and ammonium sulfate-precipitated states. The ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(93)81486-3
更新日期:1993-04-01 00:00:00