Abstract:
:Here we present a model for maltodextrin translocation through maltoporin channels. In a first step, our theoretical analysis does consider the case of a single binding site for a given substrate in a structurally unaffected channel with a possibly different entrance barrier on either side. It is shown how by means of conventional electrical conductance measurements (including current noise analysis) the basic equilibrium and rate constants can be determined as functions of the applied voltage. Then also the net translocation rate of the substrate becomes accessible quantitatively. This most simple model mechanism has been extended to include a voltage-dependent fast conformational change of the channel that prevents the binding process. The so developed approach has been tested with experimental data for a single maltoporin trimer being reconstituted in black lipid membranes when studied in the presence of maltohexaose as the substrate. The experimental results turned out to be clearly incompatible with binding alone. They are, however, very satisfactorily fitted by pertinent theoretical curves if also inhibition of binding by a conformational transition is taken into account. Accordingly, quantitative evaluations of the underlying parameters and eventually of the translocation rate have been carried out successfully. Our analysis reveals a set of parameters necessary for an optimal translocation that nicely corresponds to natural conditions.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Schwarz G,Danelon C,Winterhalter Mdoi
10.1016/S0006-3495(03)70025-3subject
Has Abstractpub_date
2003-05-01 00:00:00pages
2990-8issue
5eissn
0006-3495issn
1542-0086pii
S0006-3495(03)70025-3journal_volume
84pub_type
杂志文章abstract::A two-dimensional stochastic model for the dynamics of microtubules in gliding-assay experiments is presented here, which includes the viscous drag acting on the moving fiber and the interaction with the kinesins. For this purpose, we model kinesin as a spring, and explicitly use parameter values to characterize the m...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)76223-6
更新日期:2001-06-01 00:00:00
abstract::Elastin-derived peptides are released from the extracellular matrix remodeling by numerous proteases and seem to regulate many biological processes, notably cancer progression. The canonical elastin peptide is VGVAPG, which harbors the XGXXPG consensus pattern, allowing interaction with the elastin receptor complex lo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2020.04.019
更新日期:2020-06-02 00:00:00
abstract::The photocycle of the photophobic receptor sensory rhodopsin II from N. pharaonis was analyzed by varying measuring wavelengths, temperature, and pH, and by exchanging H2O with D2O. The data can be satisfactorily modeled by eight exponents over the whole range of modified parameters. The kinetic data support a model s...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(98)77588-5
更新日期:1998-08-01 00:00:00
abstract::Titin is a giant filamentous polypeptide of multidomain construction spanning between the Z- and M-lines of the cardiac muscle sarcomere. Extension of the I-band segment of titin gives rise to a force that underlies part of the diastolic force of cardiac muscle. Titin's force arises from its extensible I-band region, ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(99)77149-3
更新日期:1999-12-01 00:00:00
abstract::The characteristic equatorial X-ray pattern from a relaxed vertebrate skeletal muscle changes when the muscle is activated. In particular, there is a simultaneous decrease in the intensity of the first reflection (I10) and increase in the intensity of the second (I11). This observed change is almost reciprocal. When c...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(78)85510-6
更新日期:1978-01-01 00:00:00
abstract::Force spectroscopy is commonly used to measure the kinetics of processes occurring in single biological molecules. These measurements involve attaching the molecule of interest to micron-sized or larger force probes via compliant linkers. Recent theoretical work has described how the properties of the probes and linke...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2016.06.011
更新日期:2016-07-26 00:00:00
abstract::The polar interface of membranes containing phosphatidylglycerol or cholesterol was studied by (2)H nuclear magnetic resonance (NMR) as a function of membrane hydration. The membranes were macroscopically aligned and hydrated with deuterium oxide. Water uptake and membrane annealing was achieved under NMR control, usi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76788-9
更新日期:2000-05-01 00:00:00
abstract::Certain environmental parameters are accessible to cells only indirectly and require an encoding step for cells to retrieve the relevant information. A prominent example is the phenomenon of quorum sensing by microorganisms, where information about cell density is encoded by means of secreted signaling molecules. The ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.05.031
更新日期:2014-07-01 00:00:00
abstract::The bacterial flagellar motor is a rotary molecular machine that rotates the helical filaments that propel swimming bacteria. Extensive experimental and theoretical studies exist on the structure, assembly, energy input, power generation, and switching mechanism of the motor. In a previous article, we explained the ge...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2009.01.023
更新日期:2009-04-22 00:00:00
abstract::Actin is one of the main components of the architecture of cells. Actin filaments form different polymer networks with versatile mechanical properties that depend on their spatial organization and the presence of cross-linkers. Here, we investigate the mechanical properties of actin bundles in the absence of cross-lin...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.07.017
更新日期:2017-09-05 00:00:00
abstract::The effects of the anionic tungsten carbonyl complex [W(CO)(5)SC(6)H(5)](-) and its fluorinated analog [W(CO)(5)SC(6)F(5)](-) on the electrical properties of the plasma membrane of mouse myeloma cells were studied by the single-cell electrorotation technique. At micromolar concentrations, both compounds gave rise to a...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76400-9
更新日期:2000-09-01 00:00:00
abstract::F-actin, a helical polymer formed by polymerization of the monomers (G-actin), plays crucial roles in various aspects of cell motility. Flexibility of F-actin has been suggested to be important for such a variety of functions. Understanding the flexibility of F-actin requires characterization of a hierarchy of dynamic...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.125302
更新日期:2008-06-01 00:00:00
abstract::The parameters of the immune response dynamics are usually estimated by the use of deterministic ordinary differential equations that relate data trends to parameter values. Since the physical basis of the response is stochastic, we are investigating the intensity of the data fluctuations resulting from the intrinsic ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.094508
更新日期:2007-05-15 00:00:00
abstract::Normal left-right patterning in vertebrates depends on the rotational movement of nodal cilia. In order to produce this ciliary motion, the activity of axonemal dyneins must be tightly regulated in a temporal and spatial manner; the specific activation pattern of the dynein motors in the nodal cilia has not been repor...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2015.05.027
更新日期:2015-07-07 00:00:00
abstract::Crystals have been grown of "sperm whale" myoglobin produced in Escherichia coli from a synthetic gene and the structure has been solved to 1.9 A resolution. Because of a remaining initiator methionine, this protein crystallizes in a different space group from native sperm whale myoglobin. The three-dimensional struct...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(90)82540-6
更新日期:1990-02-01 00:00:00
abstract::In this article, we demonstrate the new method of pulsed interleaved excitation (PIE), which can be used to extend the capabilities of multiple-color fluorescence imaging, fluorescence cross-correlation spectroscopy (FCCS), and single-pair fluorescence resonance energy transfer (spFRET) measurements. In PIE, multiple ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.064766
更新日期:2005-11-01 00:00:00
abstract::Protein solubility in aqueous solutions depends in a complicated and not well understood way on pH, salt type, and salt concentration. Why for instance does the use of two different monovalent salts, potassium thiocyanate and potassium chloride, produce such different results? One important and previously neglected so...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74512-3
更新日期:2003-08-01 00:00:00
abstract::We present a theory for proton diffusion through an immobilized protein membrane perfused with an electrolyte and a buffer. Using a Nernst-Planck equation for each species and assuming local charge neutrality, we obtain two coupled nonlinear diffusion equations with new diffusion coefficients dependent on the concentr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(79)85274-1
更新日期:1979-01-01 00:00:00
abstract::Sickle hemoglobin forms long, multistranded polymers that account for the pathophysiology of the disease. The molecules in these polymers make significant contacts along the polymer axis (i.e., axial contacts) as well as making diagonally directed contacts (i.e., lateral contacts). The axial contacts do not engage the...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2013.09.032
更新日期:2013-11-05 00:00:00
abstract::Recent suggestions of nanoscale heat confinement on the surface of synthetic and biogenic magnetic nanoparticles during heating by radio frequency-alternating magnetic fields have generated intense interest because of the potential utility of this phenomenon for noninvasive control of biomolecular and cellular functio...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2020.01.028
更新日期:2020-03-24 00:00:00
abstract::Integrin-mediated signaling is crucial for cell-substrate adhesion and can be triggered from both intra- and extracellular interactions. Although talin binding is sufficient for inside-out activation of integrin, other cytoplasmic proteins such as α-actinin and filamin can directly interfere with talin-mediated integr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.06.064
更新日期:2017-08-22 00:00:00
abstract::Single-stranded junctions/loops are frequently occurring structural motifs in nucleic acid structures. Due to the polyanionic nature of the nucleic acid backbone, metal ions play a crucial role in the loop stability. Here we use the tightly bound ion theory, which can account for the possible ion correlation and ensem...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.131524
更新日期:2008-07-01 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::We have studied the combined effects of X-irradiation and nitrogen mustard treatment on the colony-forming ability of Chinese hamster cells. In contrast to X-irradiation, nitrogen mustard acting by itself yields an exponential dose-effect relationship. Moreover, whether delivered in immediate sequence or after varying...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(69)86439-8
更新日期:1969-09-01 00:00:00
abstract::Magic-angle spinning nuclear magnetic resonance is well suited for the study of membrane proteins in the nativelike lipid environment. However, the natural cellular membrane is invariably more complex than the proteoliposomes most often used for solid-state NMR (SSNMR) studies, and differences may affect the structure...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2015.02.018
更新日期:2015-04-07 00:00:00
abstract::G-protein-coupled receptors (GPCRs) are important membrane proteins that mediate cellular signaling and represent primary targets for about one-third of currently marketed drugs. Recent x-ray crystallographic studies identified distinct conformations of GPCRs in the active and inactive states. An allosteric sodium ion...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2015.03.003
更新日期:2015-04-07 00:00:00
abstract::The cytoplasm of a living cell is a dynamic environment through which intracellular components must move and mix. In motile, rapidly deforming cells such as human neutrophils, bulk cytoplasmic flow couples cell deformation to the transport and dispersion of cytoplasmic particles. Using particle-tracking measurements i...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.09.009
更新日期:2017-11-07 00:00:00
abstract::Deuterium nuclear magnetic resonance was used to monitor lipid acyl-chain orientational order in suspensions of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) containing Ca(2+) and the lung surfactant proteins SP-A and SP-B separately and together. To distinguish between protein-lipid...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.102681
更新日期:2007-07-01 00:00:00
abstract::In this article, we explore the information content of molecular force-field calculations. We make use of exhaustive lattice models of molecular conformations and reduced alphabet sequences to determine the relative resolving power of pairwise interaction-based force fields. We find that sequence-specific interactions...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.059618
更新日期:2005-11-01 00:00:00
abstract::Dual-color fluorescence cross-correlation analysis is a powerful tool for probing interactions of different fluorescently labeled molecules in aqueous solution. The concept is the selective observation of coordinated spontaneous fluctuations in two separate detection channels that unambiguously reflect the existence o...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)73935-0
更新日期:2002-09-01 00:00:00