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Protein motors for future molecular and
nano-bio-machines
D.Y. Li
Department of Chemical and Materials Engineering
Department of Bio-medical Engineering
University of Alberta, Edmonton, Alberta, Canada T6G 2V4
Living creatures move, driven by motor proteins
Muscle contraction is achieved by the interaction between actin filaments and motor proteins
WHIPLIKE TAILS, found on many
bacteria, are propelled by protein
motors. The tiny biochemical motor
turns a rotary shaft that spins the tails,
or flagella, and allows the bacteria,
such as these E. coli, to move through
liquid.
Classification of protein motors
Type of
motion
Filaments
Actin filament
( 8 nm in dia. )
Motors
Myosin
Energy
source
Functions
ATP
Membrane transport
Muscle contraction
Cytokinesis
Cytoplasmic streaming
ATP
Cilia & flagella
Vesicle transport
Spindle movement
Linear
Microtubule
( 25 nm in dia. )
Dynein
Kinesin
Flagella motor of bacteria
Rotary
ATP synthase
F1-ATPase
Proton
gradient
Flagellar rotation
ATP synthesis
ATP
Burgess et al,
Nature (2003)
Burgess-Oiwa model (linear motion)
50 nm
Protein motors have the potential as a biological
engine for nano-bio-devices
Protein motors would be useful as engines to drive bio-filaments
such as microtubules (as a medium) for power transfer in future
bio-nano-devices
Since a number of bio-filaments are involved, the interaction
between the filaments influences their movement:
1) Microtubule joining or interaction
2) Self-organization of microtubules
Microtubule joining
When meeting, a microtubule has the tendency to move together with the other, no matter they
move in similar directions or in opposite directions. The joining involves bending and rotation of
microtubules, which is energy-controlled.
Self-organization of microtubules
When a large number of microtubules moving in a system, they may move in a self-organized
form with the formation of circular patterns as shown in the left-hand side figure. A computer
simulation study suggests that the self-organization of microtubules is caused by microtubule
bias and their mutual interaction or joining (see the right-hand side movie).
The circular patterns from the self-organized
movement of microtubules
Computer simulated self-organization of microtubules
driven by dynein c (one type of protein motors).