Tuesday, September 21, 1999 Published at 16:09 GMT 17:09 UK
Scientists make molecular motor
By BBC News Online Science Editor Dr David Whitehouse
It has just 78 atoms, took four years to build and it has a spindle that takes hours to rotate but it could be the forerunner of a revolution.
Attempts by scientists to produce molecule-sized machines have produced a toolbox of parts, gears, rotors, switches, turnstiles but no one has produced a molecular motor, until now.
Two molecular motors are reported in the journal Nature.
One was constructed by Dr T Ross Kelly and colleagues of Boston College in Massachusetts. One of his motivations was to understand the molecular motors that are found in all forms of life.
"There are a lot of biological motors in nature," he told BBC News Online, "muscles, sperm etc., but although biologists have studied them for many decades they still do not understand how they work on a molecular level. Now we may have a clue."
The diminutive motor consists of 78 atoms arranged in two molecules, a three sided spindle composed of star-shaped molecules and a base plate molecule on which it rests.
"It is a bit like a ratchet, it can turn one way but not the other," says Dr Kelly.
The wheel gets the energy required to turn from a molecule called ATP. This is the energy source of biological cells. ATP is a molecule with a lot of internal energy which it can be persuaded to release.
Scientists say that understanding how the motor works will broaden our understanding of many fundamental biological processes.
"Nature tends to conserve solutions," points out Dr Kelly, "it does not solve ten similar problems in ten different ways. It finds a common solution. So our molecular motor may help us understand natural molecular motors in cells."
At the moment the motor is not much good for anything, except to demonstrate a principle.
"It does not turn very quickly," he adds. "It takes several hours for the three-spindled wheel to make one revolution. Our next step is to speed it up."
The other molecular motor reported by Nature has been constructed by Dutch and Japanese scientists.
Using a specially assembled carbon molecule, they have been able to make part of it rotate in one direction, taking only four steps to make a complete revolution.
This motor is not powered by ATP but by light and changes in temperature.