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

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.

Collective Transport by Multiple Molecular Motors

2012 ◽  
Author(s):  
Woochul Nam ◽  
Bogdan I. Epureanu
Keyword(s):  
Single Molecule ◽  
Molecular Motors ◽  
External Load ◽  
Power Loss ◽  
Molecular Motor ◽  
Mechanistic Model ◽  
Force Distribution ◽  
Collective Transport ◽  
Correlated Motions ◽  
Highly Correlated

Kinesin is a processive molecular motor that transports various cellular cargoes by converting chemical energy into mechanical movements. Although the motion of a single molecule has been characterized in several studies, the dynamics of collective transports remains unresolved. Since the fluctuating load acting on each motor is an important factor in the collective transport, the relation between the varying force and the chemical reaction of kinesin is considered using a stochastic mechanistic model. Several metrics are developed to measure the correlation among the motion of the motors, the force distribution, and the power loss. It is shown that both large external load and stiff cargo linkers cause highly correlated motions of motors. However, these correlated motions do not lead to faster collective transport.

Molecular Motors: Force and Movement Generated by Single Myosin II Molecules

Physiology ◽  
2002 ◽  
Vol 17 (5) ◽  
pp. 213-218 ◽  
Author(s):  
Caspar Rüegg ◽  
Claudia Veigel ◽  
Justin E. Molloy ◽  
Stephan Schmitz ◽  
John C. Sparrow ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Single Molecule ◽  
Molecular Motors ◽  
Molecular Motor ◽  
Myosin Ii ◽  
Force Production ◽  
Myosin Isoforms ◽  
Single Molecule Level ◽  
Recent Developments ◽  
Muscle Myosin

Muscle myosin II is an ATP-driven, actin-based molecular motor. Recent developments in optical tweezers technology have made it possible to study movement and force production on the single-molecule level and to find out how different myosin isoforms may have adapted to their specific physiological roles.

scholarly journals A Generalized Kinetic Model for Coupling between Stepping and ATP Hydrolysis of Kinesin Molecular Motors

2019 ◽  
Vol 20 (19) ◽  
pp. 4911 ◽  
Author(s):  
Xie ◽  
Guo ◽  
Chen
Keyword(s):  
Kinetic Model ◽  
Atpase Activity ◽  
Single Molecule ◽  
Rate Constants ◽  
Molecular Motors ◽  
Atp Hydrolysis ◽  
Power Production ◽  
Wild Type ◽  
Chemomechanical Coupling ◽  
Generalized Kinetic Model

A general kinetic model is presented for the chemomechanical coupling of dimeric kinesin molecular motors with and without extension of their neck linkers (NLs). A peculiar feature of the model is that the rate constants of ATPase activity of a kinesin head are independent of the strain on its NL, implying that the heads of the wild-type kinesin dimer and the mutant with extension of its NLs have the same force-independent rate constants of the ATPase activity. Based on the model, an analytical theory is presented on the force dependence of the dynamics of kinesin dimers with and without extension of their NLs at saturating ATP. With only a few adjustable parameters, diverse available single molecule data on the dynamics of various kinesin dimers, such as wild-type kinesin-1, kinesin-1 with mutated residues in the NLs, kinesin-1 with extension of the NLs and wild-type kinesin-2, under varying force and ATP concentration, can be reproduced very well. Additionally, we compare the power production among different kinesin dimers, showing that the mutation in the NLs reduces the power production and the extension of the NLs further reduces the power production.

scholarly journals Quantifying the Heat Dissipation from Molecular Motor’s Transport Properties in Nonequilibrium Steady States

2016 ◽  
Author(s):  
Wonseok Hwang ◽  
Changbong Hyeon
Keyword(s):  
Single Molecule ◽  
Molecular Motors ◽  
Heat Dissipation ◽  
Molecular Motor ◽  
Diffusion Constant ◽  
Nonequilibrium Steady States ◽  
Directed Motion ◽  
Mean Velocity ◽  
Self Diffusion ◽  
Brownian Particles

Theoretical analysis, which maps single molecule time trajectories of a molecular motor onto unicyclic Markov processes, allows us to evaluate the heat dissipated from the motor and to elucidate its dependence on the mean velocity and diffusivity. Unlike passive Brownian particles in equilibrium, the velocity and diffusion constant of molecular motors are closely inter-related to each other. In particular, our study makes it clear that the increase of diffusivity with the heat production is a natural outcome of active particles, which is reminiscent of the recent experimental premise that the diffusion of an exothermic enzyme is enhanced by the heat released from its own catalytic turnover. Compared with freely diffusing exothermic enzymes, kinesin-1 whose dynamics is confined on one-dimensional tracks is highly efficient in transforming conformational fluctuations into a locally directed motion, thus displaying a significantly higher enhancement in diffusivity with its turnover rate. Putting molecular motors and freely diffusing enzymes on an equal footing, our study offers thermodynamic basis to understand the heat enhanced self-diffusion of exothermic enzymes.

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

Nanoscale ◽  
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...

scholarly journals Molecular motors: forty years of interdisciplinary research

2011 ◽  
Vol 22 (21) ◽  
pp. 3936-3939 ◽  
Author(s):  
James A. Spudich
Keyword(s):  
Single Molecule ◽  
Molecular Motors ◽  
Atp Hydrolysis ◽  
Molecular Motor ◽  
Single Molecule Level ◽  
In Vitro Motility ◽  
Nonmuscle Cell ◽  
Nonmuscle Cells ◽  
City Plan

A mere forty years ago it was unclear what motor molecules exist in cells that could be responsible for the variety of nonmuscle cell movements, including the “saltatory cytoplasmic particle movements” apparent by light microscopy. One wondered whether nonmuscle cells might have a myosin-like molecule, well known to investigators of muscle. Now we know that there are more than a hundred different molecular motors in eukaryotic cells that drive numerous biological processes and organize the cell's dynamic city plan. Furthermore, in vitro motility assays, taken to the single-molecule level using techniques of physics, have allowed detailed characterization of the processes by which motor molecules transduce the chemical energy of ATP hydrolysis into mechanical movement. Molecular motor research is now at an exciting threshold of being able to enter into the realm of clinical applications.

Highlights from the Asia Pacific Region

2014 ◽  
Vol 03 (02) ◽  
pp. 25-36
Author(s):  
Keyword(s):  
Conformational Changes ◽  
Molecular Motors ◽  
Molecular Motor ◽  
Energy Conversion Efficiency ◽  
Point Of View ◽  
Asia Pacific ◽  
Water Molecules ◽  
Surrounding Water ◽  
Remarkable Feature ◽  
Chemomechanical Coupling

Molecular motors are nanometer-sized mechanoenzymes that work in living cells. Many motors convert chemical energy into work through their cyclic conformational changes that are coupled with nucleotide hydrolysis. The energy conversion efficiency of molecular motors is in general high. Despite extensive studies on this topic, detailed mechanism of chemomechanical coupling from molecular point of view still remains elusive. One remarkable feature that discriminates the molecular motor proteins from human-made machines is that molecular motors work in aqueous solution, interacting with many water molecules. One of the key approaches to address the molecular mechanism of the molecular motors is to understand the role of the intermolecular interaction with surrounding water molecules by modulating the interaction with water molecules.

Direct Observation of Single-Molecule Stick–Slip Motion in Polyamide Single Crystals

2018 ◽  
Vol 7 (6) ◽  
pp. 762-766 ◽  
Author(s):  
Xiujuan Lyu ◽  
Yu Song ◽  
Wei Feng ◽  
Wenke Zhang
Keyword(s):  
Single Crystals ◽  
Direct Observation ◽  
Single Molecule ◽  
Stick Slip ◽  
Stick Slip Motion ◽  
Slip Motion

scholarly journals Acceleration of DNA Replication of Klenow Fragment by Small Resisting Force

2021 ◽  
Vol 38 (11) ◽  
pp. 118701
Author(s):  
Yu-Ru Liu ◽  
Peng-Ye Wang ◽  
Wei Li ◽  
Ping Xie
Keyword(s):  
Dna Replication ◽  
External Force ◽  
Single Molecule ◽  
Molecular Motors ◽  
Dna Polymerases ◽  
Maximum Velocity ◽  
Magnetic Tweezers ◽  
Coupling Mechanism ◽  
Klenow Fragment ◽  
Chemomechanical Coupling

DNA polymerases are an essential class of enzymes or molecular motors that catalyze processive DNA syntheses during DNA replications. A critical issue for DNA polymerases is their molecular mechanism of processive DNA replication. We have proposed a model for chemomechanical coupling of DNA polymerases before, based on which the predicted results have been provided about the dependence of DNA replication velocity upon the external force on Klenow fragment of DNA polymerase I. Here, we performed single molecule measurements of the replication velocity of Klenow fragment under the external force by using magnetic tweezers. The single molecule data verified quantitatively the previous theoretical predictions, which is critical to the chemomechanical coupling mechanism of DNA polymerases. A prominent characteristic for the Klenow fragment is that the replication velocity is independent of the assisting force whereas the velocity increases largely with the increase of the resisting force, attains the maximum velocity at about 3.8 pN and then decreases with the further increase of the resisting force.

scholarly journals Single-molecule FRET dynamics of molecular motors in an ABEL Trap

2020 ◽  
Author(s):  
Maria Dienerowitz ◽  
Jamieson A. L. Howard ◽  
Steven D. Quinn ◽  
Frank Dienerowitz ◽  
Mark C. Leake
Keyword(s):  
Dna Replication ◽  
Single Molecule ◽  
Conformational Changes ◽  
Molecular Motors ◽  
Rational Design ◽  
Molecular Motor ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Observation Time

AbstractSingle-molecule Förster resonance energy transfer (smFRET) of molecular motors provides transformative insights into their dynamics and conformational changes both at high temporal and spatial resolution simultaneously. However, a key challenge of such FRET investigations is to observe a molecule in action for long enough without restricting its natural function. The Anti-Brownian ELectrokinetic Trap (ABEL trap) sets out to combine smFRET with molecular confinement to enable observation times of up to several seconds while removing any requirement of tethered surface attachment of the molecule in question. In addition, the ABEL trap’s inherent ability to selectively capture FRET active molecules accelerates the data acquisition process. Here we exemplify the capabilities of the ABEL trap in performing extended timescale smFRET measurements on the molecular motor Rep, which is crucial for removing protein blocks ahead of the advancing DNA replication machinery and for restarting stalled DNA replication. We are able to monitor single Rep molecules up to 6 s with 1 ms time resolution capturing multiple conformational switching events during the observation time. Here we provide a step-by-step guide for the rational design, construction and implementation of the ABEL trap for smFRET detection of Rep in vitro. We include details of how to model the electric potential at the trap site and use Hidden Markov analysis of the smFRET trajectories.

Sign in / Sign up

Export Citation Format

Share Document