scholarly journals 2P191 Energy landscape of the interaction between an actin filament and a myosin molecule

2005 ◽  
Vol 45 (supplement) ◽  
pp. S167
Author(s):  
M. Takano
Keyword(s):  
Actin Filament ◽  
Energy Landscape ◽  
Myosin Molecule

J021011 Energy landscape between adjacent subunits in cofilin-decorated actin filament

2013 ◽  
Vol 2013 (0) ◽  
pp. _J021011-1-_J021011-3
Author(s):  
Tetsuya FUJII ◽  
Yasuhiro INOUE ◽  
Taiji ADACHI
Keyword(s):  
Actin Filament ◽  
Energy Landscape

scholarly journals Allostery and molecular stripping mechanism in profilin regulated actin filament growth

2021 ◽  
Author(s):  
Weiwei Zhang ◽  
Yi Cao ◽  
Wenfei Li ◽  
Wei Wang
Keyword(s):  
Conformational Change ◽  
Actin Filament ◽  
Crucial Role ◽  
Ternary Complex ◽  
Energy Landscape ◽  
Growth Dynamics ◽  
Landscape Model ◽  
Allosteric Coupling ◽  
Twist Conformation ◽  
Pointed End

Abstract Profilin is an actin-sequestering protein and plays key role in regulating the polarized growth of actin filament. Binding of profilin to monomeric actin (G-actin) allows continuous elongation at the barbed end, but not the pointed end, of filament. How G-actin exchanges between the profilin-sequestered state and the filament state (F-actin) to support the barbed end elongation is not well understood. Here, we investigate the involved molecular mechanism by constructing a multi-basin energy landscape model and performing molecular simulations. We showed that the actin exchanging occurs by forming a ternary complex. The interactions arising from the barbed end binding drive the conformational change of the attached G-actin in the ternary complex from twist conformation to more flatten conformation without involving the change of nucleotide state, which in turn destabilizes the actin-profilin interface and promotes the profilin stripping event through allosteric coupling. We also showed that attachment of free profilin to the barbed end induces conformational change of the barbed end actin and facilitates its stripping from the filament. These results suggest a molecular stripping mechanism of the polarized actin filament growth dynamics controlled by the concentrations of the actin-profilin dimer and the free profilin, in which the allosteric feature of the monomeric actin plays crucial role.

Actomyosin interaction in striated muscle

1997 ◽  
Vol 77 (3) ◽  
pp. 671-697 ◽  
Author(s):  
R. Cooke
Keyword(s):  
Actin Filament ◽  
Striated Muscle ◽  
Myosin Head ◽  
Three Dimensional ◽  
Step Length ◽  
Myosin Molecule ◽  
Actin Monomer ◽  
Active Fiber ◽  
Actomyosin Interaction ◽  
Dimensional Crystal

The mechanics of the actomyosin interaction have been extensively studied using the organized filament array of striated muscle. However, the extrapolation of these data to the events occurring at the level of a single actomyosin interaction has not been simple. Problems arise in part because an active fiber has an ensemble of myosin heads that are spread out through the various steps of the active cycle, and it is likely that only a small fraction of the heads are generating tension at any given time. More recently, two new approaches have greatly extended our knowledge of the actomyosin interaction. First, the three-dimensional crystal structures of both the actin monomer and the myosin head have been determined, and these structures have been fit to lower resolution images to give atomic models of the actin filament and of the actin filament decorated by myosin heads. Second, the technology to measure picoNewton forces and nanometer distances has provided direct determinations of the force and step length generated by a single myosin molecule interacting with a single actin filament. This review synthesizes the existing mechanical data obtained from the more-organized array of the muscle filament with the results obtained by these two technologies.

Toward an alignment of the actin molecule within the actin filament

1983 ◽  
Vol 41 ◽  
pp. 450-451
Author(s):  
P.R. Smith ◽  
W.E. Fowler ◽  
U. Aebi
Keyword(s):  
Actin Filament ◽  
Diffraction Data ◽  
Quantitative Estimate ◽  
Molecular Model ◽  
Quantitative Comparison ◽  
Regulatory Proteins ◽  
Essential Information ◽  
X Ray ◽  
Maximum Resolution ◽  
Lack Of Information

An understanding of the specific interactions of actin with regulatory proteins has been limited by the lack of information about the structure of the actin filament. Molecular actin has been studied in actin-DNase I complexes by single crystal X-ray analysis, to a resolution of about 0.6nm, and in the electron microscope where two dimensional actin sheets have been reconstructed to a maximum resolution of 1.5nm. While these studies have shown something of the structure of individual actin molecules, essential information about the orientation of actin in the filament is still unavailable.The work of Egelman & DeRosier has, however, suggested a method which could be used to provide an initial quantitative estimate of the orientation of actin within the filament. This method involves the quantitative comparison of computed diffraction data from single actin filaments with diffraction data derived from synthetic filaments constructed using the molecular model of actin as a building block. Their preliminary work was conducted using a model consisting of two juxtaposed spheres of equal size.

The 3-Dimensional Molecular Structure of the Actin Filament Revisited

1985 ◽  
Vol 43 ◽  
pp. 480-481
Author(s):  
U. Aebi ◽  
R. Millonig ◽  
H. Salvo
Keyword(s):  
Actin Filament ◽  
Supramolecular Assembly ◽  
Specimen Preparation ◽  
X Ray Diffraction ◽  
Single Filament ◽  
X Ray ◽  
3 Dimensional ◽  
Filament Diameter ◽  
Preparation Conditions ◽  
Apparent Diameter

To date, most 3-D reconstructions of undecorated actin filaments have been obtained from actin filament paracrystal data (for refs, see 1,2). However, due to the fact that (a) the paracrystals may be several filament layers thick, and (b) adjacent filaments may sustantially interdigitate, these reconstructions may be subject to significant artifacts. None of these reconstructions has permitted unambiguous tracing or orientation of the actin subunits within the filament. Furthermore, measured values for the maximal filament diameter both determined by EM and by X-ray diffraction analysis, vary between 6 and 10 nm. Obviously, the apparent diameter of the actin filament revealed in the EM will critically depend on specimen preparation, since it is a rather flexible supramolecular assembly which can easily be bent or distorted. To resolve some of these ambiguities, we have explored specimen preparation conditions which may preserve single filaments sufficiently straight and helically ordered to be suitable for single filament 3-D reconstructions, possibly revealing molecular detail.

Configurational Diffusion on a Locally Connected Correlated Energy Landscape; Application to Finite, Random Heteropolymers

1997 ◽  
Vol 7 (3) ◽  
pp. 395-421 ◽  
Author(s):  
Jin Wang ◽  
Steven S. Plotkin ◽  
Peter G. Wolynes
Keyword(s):  
Energy Landscape

Revisiting the High-Pressure Properties of the Metal-Organic Frameworks ZIF-8 and ZIF-67

2020 ◽  
Author(s):  
Pia Vervoorts ◽  
Stefan Burger ◽  
Karina Hemmer ◽  
Gregor Kieslich
Keyword(s):  
High Pressure ◽  
State Of The Art ◽  
Energy Landscape ◽  
Structural Flexibility ◽  
Zeolitic Imidazolate Frameworks ◽  
Stimuli Responsive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Open Questions ◽  
Metal Organic

The zeolitic imidazolate frameworks ZIF-8 and ZIF-67 harbour a series of fascinating stimuli responsive properties. Looking at their responsitivity to hydrostatic pressure as stimulus, open questions exist regarding the isotropic compression with non-penetrating pressure transmitting media. By applying a state-of-the-art high-pressure powder X-ray diffraction setup, we revisit the high-pressure behaviour of ZIF-8 and ZIF-67 up to <i>p</i> = 0.4 GPa in small pressure increments. We observe a drastic, reversible change of high-pressure powder X-ray diffraction data at <i>p</i> = 0.3 GPa, discovering large volume structural flexibility in ZIF-8 and ZIF-67. Our results imply a shallow underlying energy landscape in ZIF-8 and ZIF-67, an observation that might point at rich polymorphism of ZIF-8 and ZIF-67, similar to ZIF-4(Zn).<br>

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