Issue Date: December 21, 2009
Tiny Molecular Track Walker
Looking to mimic mighty biomolecular machines, such as kinesin and myosin, chemists at Scotland’s University of Edinburgh have developed a synthetic small molecule that walks, foot over foot, down a molecular track when prompted by changes in pH (Nat. Chem., DOI: 10.1038/nchem.481). Created by David A. Leigh, Max von Delius, and Edzard M. Geertsema, the 21-atom walking unit (red) has one sulfur foot and one hydrazide foot, which travel along the track’s benzaldehyde and benzylic disulfide footholds (green and blue, respectively). Acidic conditions make the sulfur foot lock itself into a disulfide bond on the track, leaving the hydrazide foot to move freely. Under basic conditions, the hydrazide foot reacts with one of the benzaldehyde footholds to form a hydrazone linkage, and the sulfur foot is set loose to stroll to a benzylic disulfide on the track. The Edinburgh researchers found that when they used a redox reaction to break the disulfide bond, they were able to make the walker travel in one direction, rather than wander back and forth. This suggests a similar system could be devised in which a molecular walker carries cargo down a much longer track of footholds, the researchers say.
- Chemical & Engineering News
- ISSN 0009-2347
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