Kinesin Walks Hand-Over-Hand

@article{Yildiz2004KinesinWH,
  title={Kinesin Walks Hand-Over-Hand},
  author={Ahmet Yildiz and Michio Tomishige and Ronald D. Vale and Paul R. Selvin},
  journal={Science},
  year={2004},
  volume={303},
  pages={676 - 678}
}
Kinesin is a processive motor that takes 8.3-nm center-of-mass steps along microtubules for each adenosine triphosphate hydrolyzed. Whether kinesin moves by a “hand-over-hand” or an “inchworm” model has been controversial. We have labeled a single head of the kinesin dimer with a Cy3 fluorophore and localized the position of the dye to within 2 nm before and after a step. We observed that single kinesin heads take steps of 17.3 ± 3.3 nm. A kinetic analysis of the dwell times between steps shows… 

How kinesin waits between steps

Two different single-molecule fluorescence resonance energy transfer (smFRET) sensors are developed to detect whether kinesin is bound to its microtubule track by one or two heads and suggest a model for how transitions in the ATPase cycle position the two kinesIn heads and drive their hand-over-hand motion.

Kinesin's step dissected with single-motor FRET

FRET is used to resolve the relative distance between the motor domains and their relative orientation, on the submillisecond timescale, during processive stepping and reveals that, during a step, a kinesin motor domain dwells in a well-defined intermediate position for ≈3 ms.

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.

Examining kinesin processivity within a general gating framework

Kinesin-1 is primarily front-head gated, and that NL length is tuned to enhance unidirectional processivity and velocity, and cysteine-light mutants do not produce wild-type motility under load.

Kinesin steps do not alternate in size.

By analyzing single-molecule stepping traces from "limping" kinesin molecules, it is able to distinguish alternate fast- and slow-phase steps and thereby to calculate the step sizes associated with the motions of each of the two heads.

Coordination between Motor Domains in Processive Kinesins*

The phenomenon of kinesin processivity is reviewed from a complementary perspective by considering specific structural features of the motor domains that underlie their coordination, and how these features contribute to its processive movement.

Understanding Kinesin's Gating Mechanism by Optical Trap

The results suggest that geometrical constraints of the neck linker domains in a walking kinesin dimer break the symmetry of the two identical heads, such that the trailing head is free to move when the leading head is unable to bind nucleotide.

Direct observation of the binding state of the kinesin head to the microtubule

A single-molecule assay is reported that can directly report head binding in a walking kinesin molecule, and it is shown that only a single head is bound to the microtubule between steps at low ATP concentrations.

Kinesin's moonwalk.

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