October 11, 2005 – A protein called kinesin has a “walking” mechanism that is very energy efficient and could be used to develop future molecular-sized machines without worries about problems caused by heat, Japanese researchers said Monday, reports the Jiji Press.
Kinesin has been known as a nanometer-scale biological motor that transports various substances between cells and helps cell division. It produces eight-nanometer steps along microtubules and usually moves forward, though sometimes going backward.
Using a technique called “optical tweezers,” the researchers, led by Osaka University Prof. Toshio Yanagida, discovered the mechanism of how kinesin sets its direction and walks one foot after another like humans.
Kinesin has sensors on its “feet” that determine which way the protein should go by interpreting thermodynamic information known as entropy, according to their report published online by Nature Chemical Biology yesterday.
The protein only consumes a very tiny amount of energy when it sets the direction, and requires no energy for a walk because it takes advantage of a phenomenon called Brown motion, in which surrounding water molecules that are moving randomly due to heat, hit kinesin’s “legs” to eventually help them take steps forward.
“When you try to make highly integrated tiny devices like computer chips, you will find heat is a big problem,” Yanagida said. “But further studying kinesin’s walking mechanism, which does not produce heat but use it, could lead to a major breakthrough.”