The more I discover about microtubules, the more intrigued I become. For an evolved fundamental dynamic machine capable of affecting cell duplication and information processing the microtubule must rank as supremely important in the networking of fundamental functional neural networks.
Optical trap provides new insights into motor molecules — nature’s ultimate nanomachines
BY MARK SHWARTZ
When it comes to nanotechnology, many researchers turn to nature for inspiration. Of particular interest to nanoengineers is the naturally occurring protein kinesin — one of several “motor molecules” that facilitate movement in living cells.
A mere ten-millionth of an inch long, kinesin is the workhorse of the cell, hauling chromosomes, neurotransmitters and other vital cargo along tiny tracks called “microtubules.” While one end of a kinesin molecule holds onto its cargo, the other end uses a strange two-headed structure to grab the microtubule and pull the cargo forward.
A two-headed kinesin molecule (green) hauls a glass bead (blue) along a microtubule (red). Using an optical trap (pink) to apply force, Steven Block and colleagues were able to control the movement of individual kinesin molecules. The wireframe schematic on the right depicts the energy barriers that kinesin has to overcome to complete a single step. Courtesy of : Joshua W. Shaevitz/Stanford University
“This is one of the most efficient engines anyone has ever seen,” Shaevitz noted. “Some estimates put it at near 100 percent efficiency. It’s an amazing little thing.”
Asbury agreed: “Kinesin is an example of where Mother Nature kicks our butt. For me, I’m motivated just by understanding how this fascinating thing works.”