Myosin filaments reversibly generate large forces in cells

We present high resolution experiments performed on elementary contractile units in cells that challenge our current understanding of molecular motor force generation. The key features are the development of a force per motor considerably larger than forces measured in single molecule experiments, a force increase followed by relaxation controlled by a characteristic displacement rather than by a characteristic force, the observation of steps at half the actin filament period even though a large number of motors are at work in an elementary contractile unit. We propose a generic two-state model of molecular motor collections with hand-over-hand contractions and we find that these unexpected observations are spontaneously emerging features of a collective motor behavior.

Download Full-text

Single-molecule mechanical study of an autonomous artificial translational molecular motor beyond bridge-burning design

Nanoscale ◽

10.1039/d1nr02296b ◽

2021 ◽

Author(s):

Xinpeng Hu ◽

Xiaodan Zhao ◽

Iong Ying Loh ◽

Jie Yan ◽

Zhisong Wang

Keyword(s):

Single Molecule ◽

Molecular Motors ◽

Molecular Motor ◽

Force Generation ◽

Single Motor ◽

Mechanical Study

A key capability of molecular motors is sustainable force generation by a single motor copy. Direct force characterization at single-motor level is still missing for artificial molecular motors, though long...

Download Full-text

The motor mechanism of myosin V: insights for muscle contraction

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2004.1576 ◽

2004 ◽

Vol 359 (1452) ◽

pp. 1829-1842 ◽

Cited By ~ 53

Author(s):

K. C. Holmes ◽

D. R. Trentham ◽

R. Simmons ◽

H. Lee Sweeney ◽

Anne Houdusse

Keyword(s):

Muscle Contraction ◽

Molecular Mechanism ◽

Single Molecule ◽

Actin Filaments ◽

Striated Muscle ◽

Structural Data ◽

Force Generation ◽

Myosin V ◽

Myosin Filaments ◽

Mechanical Transduction

It is 50 years since the sliding of actin and myosin filaments was proposed as the basis of force generation and shortening in striated muscle. Although this is now generally accepted, the detailed molecular mechanism of how myosin uses adenosine triphosphate to generate force during its cyclic interaction with actin is only now being unravelled. New insights have come from the unconventional myosins, especially myosin V. Myosin V is kinetically tuned to allow movement on actin filaments as a single molecule, which has led to new kinetic, mechanical and structural data that have filled in missing pieces of the actomyosin–chemo–mechanical transduction puzzle.

Download Full-text

The method of replication affects metal film granularity and resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155517 ◽

1989 ◽

Vol 47 ◽

pp. 708-709

Author(s):

George C. Ruben

Keyword(s):

Electron Beam ◽

High Resolution ◽

Film Thickness ◽

Single Molecule ◽

Metal Film ◽

Vertical Surface ◽

High Resolution Imaging ◽

Controllable Factors ◽

Resolution Imaging

Single molecule resolution in electron beam sensitive, uncoated, noncrystalline materials has been impossible except in thin Pt-C replicas ≤ 150Å) which are resistant to the electron beam destruction. Previously the granularity of metal film replicas limited their resolution to ≥ 20Å. This paper demonstrates that Pt-C film granularity and resolution are a function of the method of replication and other controllable factors. Low angle 20° rotary , 45° unidirectional and vertical 9.7±1 Å Pt-C films deposited on mica under the same conditions were compared in Fig. 1. Vertical replication had a 5A granularity (Fig. 1c), the highest resolution (table), and coated the whole surface. 45° replication had a 9Å granulartiy (Fig. 1b), a slightly poorer resolution (table) and did not coat the whole surface. 20° rotary replication was unsuitable for high resolution imaging with 20-25Å granularity (Fig. 1a) and resolution 2-3 times poorer (table). Resolution is defined here as the greatest distance for which the metal coat on two opposing faces just grow together, that is, two times the apparent film thickness on a single vertical surface.

Download Full-text

Faculty Opinions recommendation of High-resolution structures of kinesin on microtubules provide a basis for nucleotide-gated force-generation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.725243697.793501772 ◽

2015 ◽

Author(s):

Linda Amos

Keyword(s):

High Resolution ◽

Force Generation

Download Full-text

Faculty Opinions recommendation of High-resolution 3D NMR structure of the KRAS proto-oncogene promoter reveals key features of a G-quadruplex involved in transcriptional regulation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.727448489.793530232 ◽

2017 ◽

Author(s):

Stephen Neidle

Keyword(s):

Transcriptional Regulation ◽

High Resolution ◽

Nmr Structure ◽

3D Nmr ◽

G Quadruplex ◽

Key Features

Download Full-text

S09A5 Single-molecule experiments of F1-ATPase correlating with the crystal structures and molecular simulation(Mechanism of F_1-ATPase Molecular Motor-A Cross Talk among Single Molecule, Structural Biology, and Molecular Simulation Studies-)

Seibutsu Butsuri ◽

10.2142/biophys.47.s13_4 ◽

2007 ◽

Vol 47 (supplement) ◽

pp. S13

Author(s):

Hiroyuki Noji

Keyword(s):

Crystal Structures ◽

Molecular Simulation ◽

Structural Biology ◽

Single Molecule ◽

Cross Talk ◽

Molecular Motor ◽

Simulation Studies ◽

F1 Atpase

Download Full-text

A model of processive walking and slipping of kinesin-8 molecular motors

Scientific Reports ◽

10.1038/s41598-021-87532-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ping Xie

Keyword(s):

Single Molecule ◽

Molecular Motors ◽

External Load ◽

Molecular Motor ◽

Velocity Versus ◽

Stick Slip ◽

Load Dependence ◽

Chemomechanical Coupling ◽

Similarities And Differences ◽

Stick Slip Motion

AbstractKinesin-8 molecular motor can move with superprocessivity on microtubules towards the plus end by hydrolyzing ATP molecules, depolymerizing microtubules. The available single molecule data for yeast kinesin-8 (Kip3) motor showed that its superprocessive movement is frequently interrupted by brief stick–slip motion. Here, a model is presented for the chemomechanical coupling of the kinesin-8 motor. On the basis of the model, the dynamics of Kip3 motor is studied analytically. The analytical results reproduce quantitatively the available single molecule data on velocity without including the slip and that with including the slip versus external load at saturating ATP as well as slipping velocity versus external load at saturating ADP and no ATP. Predicted results on load dependence of stepping ratio at saturating ATP and load dependence of velocity at non-saturating ATP are provided. Similarities and differences between dynamics of kinesin-8 and that of kinesin-1 are discussed.

Download Full-text

Studies of Conformational Changes of Tubulin Induced by Interaction with Kinesin Using Atomistic Molecular Dynamics Simulations

International Journal of Molecular Sciences ◽

10.3390/ijms22136709 ◽

2021 ◽

Vol 22 (13) ◽

pp. 6709

Author(s):

Xiao-Xuan Shi ◽

Peng-Ye Wang ◽

Hong Chen ◽

Ping Xie

Keyword(s):

Molecular Dynamics ◽

High Resolution ◽

Binding Energy ◽

Molecular Dynamics Simulations ◽

Conformational Changes ◽

Weak Interactions ◽

Molecular Motor ◽

Structural Data ◽

Calculated Binding Energy ◽

Dynamics Simulations

The transition between strong and weak interactions of the kinesin head with the microtubule, which is regulated by the change of the nucleotide state of the head, is indispensable for the processive motion of the kinesin molecular motor on the microtubule. Here, using all-atom molecular dynamics simulations, the interactions between the kinesin head and tubulin are studied on the basis of the available high-resolution structural data. We found that the strong interaction can induce rapid large conformational changes of the tubulin, whereas the weak interaction cannot. Furthermore, we found that the large conformational changes of the tubulin have a significant effect on the interaction of the tubulin with the head in the weak-microtubule-binding ADP state. The calculated binding energy of the ADP-bound head to the tubulin with the large conformational changes is only about half that of the tubulin without the conformational changes.

Download Full-text