Abstract:
:Despite growing interest in light-driven ion pumps for use in optogenetics, current estimates of their transport rates span two orders of magnitude due to challenges in measuring slow transport processes and determining protein concentration and/or orientation in membranes in vitro. In this study, we report, to our knowledge, the first direct quantitative measurement of light-driven Cl- transport rates of the anion pump halorohodopsin from Natronomonas pharaonis (NpHR). We used light-interfaced voltage clamp measurements on NpHR-expressing oocytes to obtain a transport rate of 219 (± 98) Cl-/protein/s for a photon flux of 630 photons/protein/s. The measurement is consistent with the literature-reported quantum efficiency of ∼30% for NpHR, i.e., 0.3 isomerizations per photon absorbed. To reconcile our measurements with an earlier-reported 20 ms rate-limiting step, or 35 turnovers/protein/s, we conducted, to our knowledge, novel consecutive single-turnover flash experiments that demonstrate that under continuous illumination, NpHR bypasses this step in the photocycle.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Feroz H,Ferlez B,Lefoulon C,Ren T,Baker CS,Gajewski JP,Lugar DJ,Gaudana SB,Butler PJ,Hühn J,Lamping M,Parak WJ,Hibberd JM,Kerfeld CA,Smirnoff N,Blatt MR,Golbeck JH,Kumar Mdoi
10.1016/j.bpj.2018.06.009subject
Has Abstractpub_date
2018-07-17 00:00:00pages
353-360issue
2eissn
0006-3495issn
1542-0086pii
S0006-3495(18)30685-4journal_volume
115pub_type
杂志文章abstract::Although ubiquitous, the processes by which bacteria colonize surfaces remain poorly understood. Here we report results for the influence of the wall shear stress on the early-stage adhesion of Pseudomonas aeruginosa PA14 on glass and polydimethylsiloxane surfaces. We use image analysis to measure the residence time o...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.11.078
更新日期:2011-01-19 00:00:00
abstract::Most of the cellular ATP in living organisms is synthesized by the enzyme F(1)F(o)-ATP synthase. The water soluble F(1) part of the enzyme can also work in reverse and utilize the chemical energy released during ATP hydrolysis to generate mechanical motion. Despite the availability of a large amount of biochemical dat...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74650-5
更新日期:2003-10-01 00:00:00
abstract::Small-angle neutron and x-ray scattering experiments have been performed on type 2 tissular transglutaminase to characterize the conformational changes that bring about Ca(2+) activation and guanosine triphosphate (GTP) inhibition. The native and a proteolyzed form of the enzyme, in the presence and in the absence of ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76860-3
更新日期:2000-06-01 00:00:00
abstract::Photosystem II catalyzes photosynthetic water oxidation in plants, green algae, and cyanobacteria. The manganese-containing active site cycles through a series of five oxidation states, S(n), where n refers to the number of oxidizing equivalents stored. In this report, reaction-induced Fourier transform infrared and e...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74680-3
更新日期:2003-10-01 00:00:00
abstract::The effects of cholesterol (Chol) on phospholipid bilayers include ordering of the fatty acyl chains, condensing of the lipids in the bilayer plane, and promotion of the liquid-ordered phase. These effects depend on the type of phospholipids in the bilayer and are determined by the nature of the underlying molecular i...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.088427
更新日期:2007-02-15 00:00:00
abstract::During the first 2 hours of Drosophila development, precisely orchestrated nuclear cleavages, cytoskeletal rearrangements, and directed membrane growth lead to the formation of an epithelial sheet around the yolk. The newly formed epithelium remains relatively quiescent during the next hour as it is patterned by mater...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2020.03.010
更新日期:2020-05-19 00:00:00
abstract::We analyzed the microstructure in the first-order laser diffraction line from both resting and tetanically contracting single twitch fibers from frog anterior tibial muscle to see if the distribution of sarcomere lengths is continuous or discrete. Measuring the distance between adjacent microstructural elements lying ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(82)84695-X
更新日期:1982-02-01 00:00:00
abstract::In a contracting muscle, myosin cross-bridges extending from thick filaments pull the interdigitating thin (actin-containing) filaments during cyclical ATP-driven interactions toward the center of the sarcomere, the structural unit of striated muscle. Cross-bridge attachments in the sarcomere have been reported to exh...
journal_title:Biophysical journal
pub_type: 杂志文章,评审
doi:10.1016/j.bpj.2020.01.002
更新日期:2020-03-10 00:00:00
abstract::We perform single-molecule flow experiments using confocal microscopy and a microfluidic device for shear rates up to 20,000 s-1 and present results for the shear-induced unraveling and elongation of tethered von Willebrand factor (VWF) multimers. Further, we employ companion Brownian dynamics simulations to help expl...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.04.025
更新日期:2019-06-04 00:00:00
abstract::We use fluorescence correlation spectroscopy and fluorescence recovery after photobleaching to study vesicle dynamics inside the synapses of cultured hippocampal neurons labeled with the fluorescent vesicle marker FM 1-43. These studies show that when the cell is electrically at rest, only a small population of vesicl...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.059295
更新日期:2005-11-01 00:00:00
abstract::Proton permeation rates across membranes of a synthetic branch-chained glycolipid, 1,3-di-O-phytanyl-2-O-(beta-D-maltotriosyl)glycerol (Mal3(Phyt)2) as well as a branch-chained phospholipid, diphytanoylphosphatidylcholine (DPhPC) were lower than those of straight-chained lipids such as egg yolk phosphatidylcholine (EP...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)75970-X
更新日期:2001-12-01 00:00:00
abstract::Calculations are reported of the time-dependent Nernst-Planck equations for a thin permeable membrane between electrolytic solutions. Charge neutrality is assumed for the time-dependent case. The response of such a membrane system to step current input is measured in terms of the time and space changes in concentratio...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/s0006-3495(65)86707-8
更新日期:1965-03-01 00:00:00
abstract::Scanning ion conductance microscopy (SICM) is a super-resolution live imaging technique that uses a glass nanopipette as an imaging probe to produce three-dimensional (3D) images of cell surface. SICM can be used to analyze cell morphology at nanoscale, follow membrane dynamics, precisely position an imaging nanopipet...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2016.04.017
更新日期:2016-05-24 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::The detection of the 1H NMR signal of myoglobin (Mb) in tissue opens an opportunity to examine its cellular diffusion property, which is central to its purported role in facilitating oxygen transport. In perfused myocardium the field-dependent transverse relaxation analysis of the deoxy Mb proximal histidyl NdeltaH in...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78305-X
更新日期:1997-11-01 00:00:00
abstract::We study theoretically the feasibility of using transverse electronic transport within a nanopore for rapid DNA sequencing. Specifically, we examine the effects of the environment and detection probes on the distinguishability of the DNA bases. We find that the intrinsic measurement bandwidth of the electrodes helps t...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.102269
更新日期:2007-10-01 00:00:00
abstract::A method for generating angular forces around sigma-bonded transition metal ions is generalized to treat pi-bonded configurations. The theoretical approach is based on an analysis of ligand-field and small-cluster Hamiltonians based on the moments of the electron state distribution. The functional forms that are obtai...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)75675-5
更新日期:2001-07-01 00:00:00
abstract::The anisotropy of the spin-lattice relaxation time (T1) and the spin-spin relaxation times (T2) of water protons in skeletal muscle tissue have been studied by the spin-echo technique. Both T1 and T2 have been measured for the water protons of the tibialis anterior muscle of mature male rats for theta = 0, 55, and 90 ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(80)85102-2
更新日期:1980-06-01 00:00:00
abstract::Biofilm infections can consist of bacterial aggregates that are an order of magnitude larger than neutrophils, phagocytic immune cells that densely surround aggregates but do not enter them. Because a neutrophil is too small to engulf the entire aggregate, it must be able to detach and engulf a few bacteria at a time ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.08.043
更新日期:2019-10-15 00:00:00
abstract::We investigate the interactions between lipid bilayers and amphiphilic peptides using a solvent-free coarse-grained simulation technique. In our model, each lipid is represented by one hydrophilic and three hydrophobic beads. The amphiphilic peptide is modeled as a hydrophobic-hydrophilic cylinder with hydrophilic cap...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.131300
更新日期:2008-11-01 00:00:00
abstract::We study a Brownian dynamics simulation model of a biopolymeric shell deformed by axial forces exerted at opposing poles. The model exhibits two distinct, linear force-extension regimes, with the response to small tensions governed by linear elasticity and the response to large tensions governed by an effective spring...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.08.034
更新日期:2017-10-17 00:00:00
abstract::The role of desolvation in protein binding kinetics is investigated using Brownian dynamics simulations in complexes in which the electrostatic interactions are relatively weak. We find that partial desolvation, modeled by a short-range atomic contact potential, is not only a major contributor to the binding free ener...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76668-9
更新日期:2000-03-01 00:00:00
abstract::Transient receptor potential (TRP) channels are members of a large family of ion channels located in membranes rich in cholesterol, some of whose functions are affected by the cholesterol content of the membrane. Here, cholesterol binding to TRPs is studied using a docking procedure that allows the transmembrane surfa...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.10.011
更新日期:2019-11-19 00:00:00
abstract::It was shown previously that a significant fraction of the myosin crossbridges is attached to actin in the skinned rabbit psoas fibers under relaxed conditions at low ionic strength and low temperature (Brenner, B., M. Schoenberg, J. M. Chalovich, L. E. Greene, and E. Eisenberg. 1982. Proc. Natl. Acad. Sci. USA. 79:72...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(89)82838-3
更新日期:1989-03-01 00:00:00
abstract::P188, a triblock copolymer of the form poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) helps seal electroporated cell membranes, arresting the leakage of intracellular materials from the damaged cells. To explore the nature of the interaction between P188 and cell membranes, we have constructed a model...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)75499-4
更新日期:2002-03-01 00:00:00
abstract::Photosynthetic organisms drive their metabolism by converting light energy into an electrochemical gradient with high efficiency. This conversion depends on the diffusion of quinones within the membrane. In purple photosynthetic bacteria, quinones reduced by the reaction center (RC) diffuse to the cytochrome bc(1) com...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.083709
更新日期:2006-11-15 00:00:00
abstract::We present a quantitative analysis of conformational changes of the nucleotide-binding subunits, MalK(2), of the maltose ATP-binding cassette importer MalFGK(2) during the transport cycle. Distance changes occurring between selected residues were monitored in the full transporter by site-directed spin-labeling electro...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.132456
更新日期:2008-09-15 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::Native cGMP-gated channels were studied in rod outer segments of the larval tiger salamander Ambystoma tigrinum. The alpha subunit of the cGMP-gated channel from bovine rods, here referred to as the wild type (w.t.), and mutant channels were heterologously expressed in Xenopus laevis oocytes. These channels were studi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79832-6
更新日期:1996-06-01 00:00:00
abstract::FKBP12 was removed from ryanodine receptors (RyRs) by incubation of rabbit skeletal muscle terminal cisternae membranes with rapamycin. The extent of FKBP12 removal was estimated by immunostaining Western blots of terminal cisternae proteins. Single FKBP12-depleted RyR channels, incorporated into planar lipid bilayers...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78654-5
更新日期:1997-01-01 00:00:00