Abstract:
:Kinesin is a motor protein that uses the energy derived from the hydrolysis of ATP to power the transport of organelles along microtubules. To probe the mechanism of this chemical-to-mechanical energy transduction reaction, the movement of microtubules across glass surfaces coated with kinesin was perturbed by raising the viscosity of the buffer solution. When the viscosity of the solution used in the low density motility assay was increased approximately 100-fold through addition of polysaccharides and polypeptides, the longer microtubules, which experienced a larger drag force from the fluid, moved more slowly than the shorter ones. The speed of movement of a microtubule depended linearly on the drag force loading the motor. At the lowest kinesin density, where dilution experiments indicated that the movement was caused by a single kinesin molecule, extrapolation of the linear relationship yielded a maximum time-averaged drag force of 4.2 +/- 0.5 pN per motor (mean +/- experimental SE). The magnitude of the force argues against one type of "ratchet" model in which the motor is hypothesized to rectify the diffusion of the microtubule; at high viscosity, diffusion is too slow to account for the observed speeds. On the other hand, our data are consistent with models in which force is a consequence of strain developed in an elastic element within the motor; these models include a different "ratchet" model (of the type proposed by A. F. Huxley in 1957) as well as "power-stroke" models.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Hunt AJ,Gittes F,Howard Jdoi
10.1016/S0006-3495(94)80537-5subject
Has Abstractpub_date
1994-08-01 00:00:00pages
766-81issue
2eissn
0006-3495issn
1542-0086pii
S0006-3495(94)80537-5journal_volume
67pub_type
杂志文章abstract::The closed-state crystal structure of prokaryotic inward rectifier, KirBac1.1, has implicated four inner helical phenylalanines near the cytoplasmic side as a possible locus of the channel gate. In the present study, we investigate whether this structural feature corresponds to the physiological pH gate of the renal i...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.051474
更新日期:2005-04-01 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::Compared to contact-mode atomic force microscopy (CMAFM), tapping-mode atomic force microscopy (TMAFM) has the advantage of allowing imaging surfaces of macromolecules, even when they are only weakly attached to the support. In this study, TMAFM is applied to two different regular protein layers whose structures are k...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(99)76966-3
更新日期:1999-08-01 00:00:00
abstract::The structure of fully hydrated gel phase dimyristoylphosphatidylcholine lipid bilayers was obtained at 10 degrees C. Oriented lipid multilayers were used to obtain high signal-to-noise intensity data. The chain tilt angle and an estimate of the methylene electron density were obtained from wide angle reflections. The...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)75333-2
更新日期:2002-12-01 00:00:00
abstract::The endoplasmic reticulum (ER) is the major compartment for the processing and quality control of newly synthesized proteins. Green fluorescent protein (GFP) was used as a noninvasive probe to determine the viscous properties of the aqueous lumen of the ER. GFP was targeted to the ER lumen of CHO cells by transient tr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(99)77438-2
更新日期:1999-05-01 00:00:00
abstract::The interaction of the nonionic surfactant dodecylmaltoside (DM) with phosphatidylcholine liposomes was investigated. Permeability alterations were detected as a change in 5(6)-carboxyfluorescein released from the interior of vesicles and bilayer solubilization as a decrease in the static light scattered by liposome s...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78812-X
更新日期:1997-04-01 00:00:00
abstract::Actin polymerization is typically initiated at specific sites in a cell by membrane-bound protein complexes, and the resulting structures are involved in specialized cellular functions, such as migration, particle uptake, or mitotic division. Here we analyze the potential of the actin system to self-organize into wave...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2008.12.3942
更新日期:2009-04-08 00:00:00
abstract::In permeabilized single fibers of fast (psoas) and slow (soleus) muscle from the rabbit, the effect of pH on isometric myofibrillar ATPase activity and force was studied at 15 degrees C, in the pH range 6.4-7.9. ATPase activity was measured photometrically by enzymatic coupling of the regeneration of ATP to the oxidat...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(94)80727-1
更新日期:1994-12-01 00:00:00
abstract::Leukocyte capture and rolling on the vascular endothelium is mediated principally by the selectin family of cell adhesion receptors. In a parallel plate flow chamber, neutrophil rolling on purified selectins or a selectin-ligand substrate was resolved by high speed videomicroscopy as a series of ratchet-like steps wit...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(99)77169-9
更新日期:1999-12-01 00:00:00
abstract::A voltage clamp study has been performed in the presynaptic terminal of the squid stellate ganglion. After blockage of the voltage-dependent sodium and potassium conductances, an inward calcium current is demonstrated. Given a step-depolarization pulse, this voltage- and time-dependent conductance has an S-shaped onse...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(81)84898-9
更新日期:1981-03-01 00:00:00
abstract::The protonation state and intracellular distribution of ellipticine were investigated in single human mammary T47D cells by confocal laser microspectrofluorimetry. In the cell nucleus, only the protonated form of ellipticine was detected as a direct consequence of its apparent pK increase upon DNA binding. Both proton...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(93)81273-6
更新日期:1993-11-01 00:00:00
abstract::This paper describes an analysis of microscopic models for the coupling between ion flow and rotation of bacterial flagella. In model I it is assumed that intersecting half-channels exist on the rotor and the stator and that the driving ion is constrained to move together with the intersection site. Model II is based ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(88)83065-0
更新日期:1988-01-01 00:00:00
abstract::Red blood cells aggregate face-to-face to form long, cylindrical, straight chains and sometimes branched structures called rouleaux. Here we extend a kinetic model developed by R. W. Samsel and A. S. Perelson (1982, Biophys. J. 37:493-514) to include both the formation and dissociation of rouleaux. We examine thermody...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(84)84225-3
更新日期:1984-04-01 00:00:00
abstract::We studied the effects of permeant ions on the gating of the large conductance Ca(2+)-activated K+ channel from rat skeletal muscle. Rb+ blockade of inward K+ current caused an increase in the open probability as though Rb+ occupancy of the pore interferes with channel closing. In support of this hypothesis, we direct...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(92)81869-6
更新日期:1992-03-01 00:00:00
abstract::Functional RNAs can fold into intricate structures using a number of different secondary and tertiary structural motifs. Many factors contribute to the overall free energy of the target fold. This study aims at quantifying the entropic costs coming from the loss of conformational freedom when the sugar-phosphate backb...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2018.03.035
更新日期:2018-05-08 00:00:00
abstract::We investigated self-adhesion between highly negatively charged aggrecan macromolecules extracted from bovine cartilage extracellular matrix by performing atomic force microscopy (AFM) imaging and single-molecule force spectroscopy (SMFS) in saline solutions. By controlling the density of aggrecan molecules on both th...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.09.002
更新日期:2010-11-17 00:00:00
abstract::In the rabbit corneal stroma, the swelling pressure, P, has been reported to have an anomalous (negative) temperature coefficient, alpha P, contradicting traditional Donnan swelling theory. A parallel-plate, diffuse double layer Gouy-Chapman model was used to resolve this discrepancy. The present model incorporates th...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(90)82584-4
更新日期:1990-03-01 00:00:00
abstract::We compared wild-type rat skeletal muscle NaChs (micro1) and a mutant NaCh (Y1586K) that has a single amino acid substitution, lysine (K) for tyrosine (Y), at position 1586 in the S6 transmembrane segment of domain 4. In Y1586K, macroscopic current decay is faster, the V(1/2) of the activation curve is shifted in the ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76635-5
更新日期:2000-02-01 00:00:00
abstract::In Shaker-like channels, the activation gate is formed at the bundle crossing by the convergence of the inner S6 helices near a conserved proline-valine-proline motif, which introduces a kink that allows for electromechanical coupling with voltage sensor motions via the S4-S5 linker. Human ether-a-go-go-related gene (...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.01.035
更新日期:2014-03-04 00:00:00
abstract::Five highly homologous epidermal growth factor receptor ligands were studied by mass spectral analysis, hydrogen/deuterium (H/D) exchange via attenuated total reflectance Fourier transform-infrared spectroscopy, and two-dimensional correlation analysis. These studies were performed to determine the order of events dur...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.125856
更新日期:2008-05-15 00:00:00
abstract::The one-dimensional information of genomic DNA is hierarchically packed inside the eukaryotic cell nucleus and organized in a three-dimensional (3D) space. Genome-wide chromosome conformation capture (Hi-C) methods have uncovered the 3D genome organization and revealed multiscale chromatin domains of compartments and ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2020.02.020
更新日期:2020-05-05 00:00:00
abstract::The phenomena reported are part of a study about the effects of ionizing radiation on membrane transport. We found that the conductance of lipid membranes in the presence of the polyene-antibiotics nystatin or amphotericin B is reduced to virtually zero following irradiation. Ion channels formed by these substances se...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(93)81343-2
更新日期:1993-01-01 00:00:00
abstract::Rhodobacter sphaeroides can swim toward a wide range of attractants (a process known as taxis), propelled by a single rotating flagellum. The reversals of motor direction that cause tumbles in Eschericia coli taxis are replaced by brief motor stops, and taxis is controlled by a complex sensory system with multiple hom...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76678-1
更新日期:2000-03-01 00:00:00
abstract::Na(+) conductance through cloned K(+) channels has previously allowed characterization of inactivation and K(+) binding within the pore, and here we have used Na(+) permeation to study recovery from C-type inactivation in human Kv1.5 channels. Replacing K(+) in the solutions with Na(+) allows complete Kv1.5 inactivati...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76486-1
更新日期:2000-11-01 00:00:00
abstract::Computer simulations suggest that the translocation of arginine through the hydrocarbon core of a lipid membrane proceeds by the formation of a water-filled defect that keeps the arginine molecule hydrated even at the center of the bilayer. We show here that adding additional arginine molecules into one of these water...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.05.038
更新日期:2011-07-06 00:00:00
abstract::The infrared spectra of tripalmitoyl glyceride confirm the tuning fork configuration previously attributed to trilauroyl glyceride (Small, D. M. 1986. Handbook of Lipid Research. Vol. 4). The acyl chains in solid tripalmitoyl glycerol, either within each molecule or between neighboring molecules, are oriented parallel...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(89)82730-4
更新日期:1989-11-01 00:00:00
abstract::During inflammation, flowing leukocytes tether to and roll on vascular surfaces through the association and dissociation of selectin/ligand bonds. The interactions of P- and L- selectins with their respective ligands exhibit catch-slip bonds, such that increasing force initially prolongs and then shortens bond lifetim...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.05.040
更新日期:2010-08-09 00:00:00
abstract::Fluorescence fluctuation spectroscopy has become an important measurement tool for investigating molecular dynamics, molecular interactions, and chemical kinetics in biological systems. Although the basic theory of fluctuation spectroscopy is well established, it is not widely recognized that saturation of the fluores...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.052779
更新日期:2005-09-01 00:00:00
abstract::The mechanical properties of cross-linked microtubule bundles were measured from outer pillar cells isolated from the mammalian inner ear. Measurements were made using a three-point bending test and were incorporated into a mathematical model designed to distinguish between the stiffness contributions from microtubule...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78255-9
更新日期:1997-10-01 00:00:00
abstract::The x-ray structure analysis of photosystem I (PS I) crystals at 4-A resolution (Schubert et al., 1997, J. Mol. Biol. 272:741-769) has revealed the distances between the three iron-sulfur clusters, labeled F(X), F(1), and F(2), which function on the acceptor side of PS I. There is a general consensus concerning the as...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76599-4
更新日期:2000-01-01 00:00:00