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

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. Living creatures move, driven by motor proteins

Classification of protein motors 50 nm Burgess-Oiwa model (linear motion) Burgess et al, Nature (2003)

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 Protein motors have the potential as a biological engine for nano-bio-devices

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).