Kinesin hydrolyses one ATP per 8-nm step

  title={Kinesin hydrolyses one ATP per 8-nm step},
  author={Mark J. Schnitzer and Steven M. Block},
Kinesin is a two-headed, ATP-dependent motor protein that moves along microtubules indiscrete steps of 8 nm. In vitro, single molecules produceprocessive movement, motors typically take ∼100steps before releasing from a microtubule . A central question relates tomechanochemical coupling in this enzyme: how many molecules ofATP are consumed per step? For the actomyosin system,experimental approaches to this issue have generated considerablecontroversy. Here we take advantage of theprocessivity… 

Kinesin Takes One 8-nm Step for Each ATP That It Hydrolyzes*

Coupling between the chemical and mechanical cycles of kinesin is tight, consistent with conventional power stroke models, and these results rule out models that require two or more ATPs/step, such as some thermal ratchet models, or that propose multiple steps powered by single ATPs.

Single kinesin molecules studied with a molecular force clamp

The kinesin cycle contains at least one load-dependent transition affecting the rate at which ATP molecules bind and subsequently commit to hydrolysis, and it is likely that at leastOne other load- dependent rate exists, affecting turnover number.

Novel ways to unravel the mechanism of kinesin

This study presents an approach that allows the observation of fluorescence intensity changes on individual kinesins with a time resolution far better than the duration of a single step, and shows that the autocorrelation of a fluorescence time trace of anindividual kinesin motor contains information at time lags down to 0.1 ms.

A mobile kinesin-head intermediate during the ATP-waiting state

This work uses ensemble and single molecule fluorescence polarization microscopy to determine the mobility and orientation of the kinesin1 heads at different ATP concentrations and in heterodimeric constructs with microtubule binding impaired in 1 head, and finds evidence for a mobile head during the ATP-waiting state.

Kinesin's processivity results from mechanical and chemical coordination between the ATP hydrolysis cycles of the two motor domains.

  • W. HancockJ. Howard
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1999
A heterodimeric one-headed kinesin is engineered and its biochemical properties are compared to those of the wild-type two-headed molecule and a pathway is proposed that defines the chemical and mechanical cycle for two-heads kines in the ADP.P(i) state.

Kinesin processivity is gated by phosphate release

It is shown that kinesin dissociation, which characterizes the end of a processive run, is gated by phosphate release following ATP hydrolysis, and the data suggest that, during processive movement, tethered-head binding occurs subsequent to hydroolysis, rather than immediately after ATP binding, as commonly suggested.


A mechanistic model of kinesin is proposed that is capable of accurately describing transient and steady-state dynamics and was used to simulate the collective behavior of coupled kinesIn motors under varying loads, cargo linker stiffnesses, and numbers of motors.

Direct observation of intermediate states during the stepping motion of kinesin-1.

High-temporal resolution dark-field microscopy was employed to directly visualize the binding and unbinding of kinesin heads to or from microtubules during processive movement, thereby explaining how the two heads coordinate to move in a hand-over-hand manner.

Processivity of the Motor Protein Kinesin Requires Two Heads

At high ATP concentration, individual single-headed kinesin molecules detached from microtubules very slowly (at a rate less than one per second), 100-fold slower than the detachment during two-headed motility, which directly supports a coordinated, hand-over-hand model in which the rapid detachment of one head in the dimer is contingent on the binding of the second head.

How kinesin waits for ATP affects the nucleotide and load dependence of the stepping kinetics

A minimal model is developed, which analytically predicts the outcomes of a number of experimental observable quantities as a function of an external resistive force and ATP concentration and predicts that the F and [T] dependence of the randomness parameters differ qualitatively depending on the waiting states.



Direct observation of single kinesin molecules moving along microtubules

A new assay is reported in which the processive movement of individual fluorescently labelled kinesin molecules along a microtubule can be visualized directly; this observation is achieved by low-background total internal reflection fluorescence microscopy in the absence of attachment of the motor to a cargo (for example, an organelle or bead).

Detection of sub-8-nm movements of kinesin by high-resolution optical-trap microscopy.

The distribution of magnitudes reveals that kinesin not only undergoes discrete 8-nm movements, in agreement with previous work, but also frequently exhibits smaller movements of about 5 nm, which is a possible explanation for these unexpected smaller movements.

Highly processive microtubule-stimulated ATP hydrolysis by dimeric kinesin head domains

STUDIES of immobilized kinesin have shown that a single dimeric molecule can maintain contact with and drive sliding of a microtubule1,2. In solution, however, native kinesin binds micro-tubules too

The movement of kinesin along microtubules.

  • J. Howard
  • Biology
    Annual review of physiology
  • 1996
Structural, mechanical, and biochemical experiments suggest that in order not to let go of a microtubule, the two heads of kinesin might move in a coordinated manner, perhaps undergoing a rotary motion.

Evidence for alternating head catalysis by kinesin during microtubule-stimulated ATP hydrolysis.

  • D. Hackney
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1994
Half-site reactivity of dimeric DKH392 is observed over a wide range of ratios of DKH 392 to microtubules and steady-state ATPase rates, indicating that it is characteristic of the mechanism of microtubule-stimulated ATP hydrolysis and not the result of a fortuitous balance of rate constants.

Bead movement by single kinesin molecules studied with optical tweezers

The results of this study are consistent with a model in which kinesin detaches briefly from the microtubule during a part of each mechanochemical cycle, rather than a models in whichKinesin remains bound at all times.

Coordinated hydrolysis explains the mechanical behavior of kinesin.

A model for force generation in kinesin is presented in which the ATP hydrolysis reactions are coordinated with the relative positions of the two heads and permits us to study the relative roles of Brownian motion and elastic deformation in the motor mechanism of kinesIn.

Pathway of processive ATP hydrolysis by kinesin

Direct measurement of the kinetics of kinesin dissociation from microtubules, the release of phosphate and ADP from kinesIn, and rebinding of kinein to the microtubule have defined the mechanism for the kines in ATPase cycle, providing an explanation for the motility differences between skeletal myosin and kinesine.

The rate-limiting step in microtubule-stimulated ATP hydrolysis by dimeric kinesin head domains occurs while bound to the microtubule.

  • D. Hackney
  • Biology, Chemistry
    The Journal of biological chemistry
  • 1994
Results suggest that microtubule-stimulated ATP hydrolysis by DKH392 may be processive with the hydrolytic of multiple ATP molecules during each diffusional encounter of DKH 392 with a microtubules.

Mechanism of microtubule kinesin ATPase.

The proposed kinetic scheme, which treats the K379 units of a dimer as independent, provides a satisfactory description of the transient and steady-state properties of the system with the possible exception of results at very low substrate concentrations.