scholarly journals Cooperative and synchronized rotation in motorized porous frameworks: impact on local and global transport properties of confined fluids

2021 ◽  
Author(s):  
Jack D. Evans ◽  
Simon Krause ◽  
Ben L. Feringa
Keyword(s):  
Transport Properties ◽  
Molecular Motors ◽  
Specific Rotation ◽  
Confined Fluids ◽  
Directed Diffusion ◽  
Global Transport

Simulations reveal the influence of rotating molecular motors and the importance of orientation and directionality for altering the transport properties of fluids. This has outlined that motors with specific rotation can generate directed diffusion.

scholarly journals Cooperative and Synchronized Rotation in Motorized Porous Frameworks: Impact on Local and Global Transport Properties of Confined Fluids

2020 ◽  
Author(s):  
Jack D. Evans ◽  
Simon Krause ◽  
Ben L. Feringa
Keyword(s):  
Transport Properties ◽  
Molecular Motors ◽  
Molecular Motor ◽  
Stimuli Responsive ◽  
Intramolecular Dynamics ◽  
Directed Diffusion ◽  
Framework Materials ◽  
Global Transport ◽  
Dynamics Simulations ◽  
Liquid States

<div>Molecules in gas and liquid states, as well as in solution, exhibit significant and random Brownian motion. Molecules in the solid-state, although strongly immobilized, can still exhibit significant intramolecular dynamics. However, in most framework materials, these intramolecular dynamics are driven by temperature, and therefore are neither controlled nor spatially or temporarily aligned. In recent years, several examples of molecular machines that allow for a stimuli-responsive control of dynamical motion, such as rotation, have been reported.</div><div><br></div><div>In this contribution, we investigate the local and global properties of a Lennard-Jones (LJ) fluid surrounding a molecular motor and consider the influence of cooperative and non-directional rotation for a molecular motor-containing pore system. This study uses classical molecular dynamics simulations to describe a minimal model, which was developed to resemble known molecular motors. The properties of an LJ liquid surrounding an isolated molecular mo-tor remain mostly unaffected by the introduced rotation. We then considered an arrangement of motors within a one-dimensional pore. Changes in diffusivity for pore sizes approaching the length of the rotor were observed, resulting from rotation of the motors. We also considered the influence of cooperative motor directionality on the directional transport properties of this con-fined fluid. Importantly, we discovered that specific unidirectional rotation of altitudinal motors can produce directed diffusion.</div><div><br></div><div>This study provides an essential insight into molecular machine-containing frameworks, highlighting the specific structural arrangements that can produce directional mass transport.</div>

scholarly journals Cooperative and Synchronized Rotation in Motorized Porous Frameworks: Impact on Local and Global Transport Properties of Confined Fluids

2020 ◽  
Author(s):  
Jack D. Evans ◽  
Simon Krause ◽  
Ben L. Feringa
Keyword(s):  
Transport Properties ◽  
Molecular Motors ◽  
Molecular Motor ◽  
Stimuli Responsive ◽  
Intramolecular Dynamics ◽  
Directed Diffusion ◽  
Framework Materials ◽  
Global Transport ◽  
Dynamics Simulations ◽  
Liquid States

<div>Molecules in gas and liquid states, as well as in solution, exhibit significant and random Brownian motion. Molecules in the solid-state, although strongly immobilized, can still exhibit significant intramolecular dynamics. However, in most framework materials, these intramolecular dynamics are driven by temperature, and therefore are neither controlled nor spatially or temporarily aligned. In recent years, several examples of molecular machines that allow for a stimuli-responsive control of dynamical motion, such as rotation, have been reported.</div><div><br></div><div>In this contribution, we investigate the local and global properties of a Lennard-Jones (LJ) fluid surrounding a molecular motor and consider the influence of cooperative and non-directional rotation for a molecular motor-containing pore system. This study uses classical molecular dynamics simulations to describe a minimal model, which was developed to resemble known molecular motors. The properties of an LJ liquid surrounding an isolated molecular mo-tor remain mostly unaffected by the introduced rotation. We then considered an arrangement of motors within a one-dimensional pore. Changes in diffusivity for pore sizes approaching the length of the rotor were observed, resulting from rotation of the motors. We also considered the influence of cooperative motor directionality on the directional transport properties of this con-fined fluid. Importantly, we discovered that specific unidirectional rotation of altitudinal motors can produce directed diffusion.</div><div><br></div><div>This study provides an essential insight into molecular machine-containing frameworks, highlighting the specific structural arrangements that can produce directional mass transport.</div>

scholarly journals Cooperatively enhanced reactivity and “stabilitaxis” of dissociating oligomeric proteins

2020 ◽  
Vol 117 (22) ◽  
pp. 11894-11900
Author(s):  
Jaime Agudo-Canalejo ◽  
Pierre Illien ◽  
Ramin Golestanian
Keyword(s):  
Transport Properties ◽  
Molecular Motors ◽  
Protein Complexes ◽  
Oligomeric Proteins ◽  
Enhanced Diffusion ◽  
Spatial Gradients ◽  
Oligomeric Form ◽  
Functional Advantage ◽  
Functional Units ◽  
Independent Association

Many functional units in biology, such as enzymes or molecular motors, are composed of several subunits that can reversibly assemble and disassemble. This includes oligomeric proteins composed of several smaller monomers, as well as protein complexes assembled from a few proteins. By studying the generic spatial transport properties of such proteins, we investigate here whether their ability to reversibly associate and dissociate may confer on them a functional advantage with respect to nondissociating proteins. In uniform environments with position-independent association–dissociation, we find that enhanced diffusion in the monomeric state coupled to reassociation into the functional oligomeric form leads to enhanced reactivity with localized targets. In nonuniform environments with position-dependent association–dissociation, caused by, for example, spatial gradients of an inhibiting chemical, we find that dissociating proteins generically tend to accumulate in regions where they are most stable, a process that we term “stabilitaxis.”

scholarly journals Active cargo positioning in antiparallel transport networks

2019 ◽  
Vol 116 (30) ◽  
pp. 14835-14842 ◽  
Author(s):  
Mathieu Richard ◽  
Carles Blanch-Mercader ◽  
Hajer Ennomani ◽  
Wenxiang Cao ◽  
Enrique M. De La Cruz ◽  
...  
Keyword(s):  
Transport Properties ◽  
Molecular Motors ◽  
Network Architecture ◽  
Actin Polymerization ◽  
Myosin Ii ◽  
Biased Random Walk ◽  
Cargo Transport ◽  
Stochastic Transport ◽  
Mixed Polarity ◽  
Myosin Va

Cytoskeletal filaments assemble into dense parallel, antiparallel, or disordered networks, providing a complex environment for active cargo transport and positioning by molecular motors. The interplay between the network architecture and intrinsic motor properties clearly affects transport properties but remains poorly understood. Here, by using surface micropatterns of actin polymerization, we investigate stochastic transport properties of colloidal beads in antiparallel networks of overlapping actin filaments. We found that 200-nm beads coated with myosin Va motors displayed directed movements toward positions where the net polarity of the actin network vanished, accumulating there. The bead distribution was dictated by the spatial profiles of local bead velocity and diffusion coefficient, indicating that a diffusion-drift process was at work. Remarkably, beads coated with heavy–mero-myosin II motors showed a similar behavior. However, although velocity gradients were steeper with myosin II, the much larger bead diffusion observed with this motor resulted in less precise positioning. Our observations are well described by a 3-state model, in which active beads locally sense the net polarity of the network by frequently detaching from and reattaching to the filaments. A stochastic sequence of processive runs and diffusive searches results in a biased random walk. The precision of bead positioning is set by the gradient of net actin polarity in the network and by the run length of the cargo in an attached state. Our results unveiled physical rules for cargo transport and positioning in networks of mixed polarity.

Microstructures and transport properties: A comparison between grain boundaries artificially produced in YBa2Cu3Ov bicrystal thin films and bulk crystals

1996 ◽  
Vol 54 ◽  
pp. 728-729
Author(s):  
X.F. Zhang ◽  
V.R. Todt ◽  
D.J. Miller ◽  
M. St. Louis-Weber ◽  
J. Talvacchio
Keyword(s):  
Thin Films ◽  
Transport Properties ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Bulk Crystals ◽  
Transmission Electron ◽  
Electromagnetic Measurements ◽  
Global Transport ◽  
Film Deposition Rate ◽  
Microstructural Studies

In order to establish the link between grain boundary (GB) structures and transport properties in superconducting materials, electromagnetic measurements and detailed microstructural studies of carefully prepared GBs are required. Frequently, artificially induced GBs prepared by thin film deposition onto bicrystal substrates are used for such studies. Recently, transmission electron microscopy (TEM) studies have revealed a meandering configuration for GBs in YBa2Cu3Oy (YBCO) thin films grown on [001] tilt SrTiO3 bicrystal substrates (Fig. la). The deviation of the meandering GBs away from the underlying substrate GBs varies from a few tens to hundreds of nanometers. We have demonstrated that the magnitude of the meander in terms of amplitude and wavelength can be reduced by lowering the film deposition rate. The meandering GBs were shown to consist of various straight facets which are a few tens to hundreds of nanometers in length. It is possible that the various segments have very different current transport behavior due to a variable misfit dislocation density. Thus, an unambiguous correlation between the microstructure and global transport properties is difficult to attain.

Co-operative transport by molecular motors

2011 ◽  
Vol 39 (5) ◽  
pp. 1211-1215 ◽  
Author(s):  
Florian Berger ◽  
Corina Keller ◽  
Melanie J.I. Müller ◽  
Stefan Klumpp ◽  
Reinhard Lipowsky
Keyword(s):  
Transport Properties ◽  
Molecular Motors ◽  
Intracellular Transport ◽  
Theoretical Framework ◽  
Theoretical Description ◽  
Transport Processes ◽  
Experimental Results ◽  
Central Problem ◽  
Recent Advances

Intracellular transport is often driven co-operatively by several molecular motors, which may belong to one or several motor species. Understanding how these motors interact and what co-ordinates and regulates their movements is a central problem in studies of intracellular transport. A general theoretical framework for the analysis of such transport processes is described, which enables us to explain the behaviour of intracellular cargos by the transport properties of individual motors and their interactions. We review recent advances in the theoretical description of motor co-operativity and discuss related experimental results.

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