Document Detail

A single synthetic small molecule that generates force against a load.
MedLine Citation:
PMID:  21857685     Owner:  NLM     Status:  Publisher    
Some biomolecules are able to generate directional forces by rectifying random thermal motions. This allows these molecular machines to perform mechanical tasks such as intracellular cargo transport or muscle contraction in plants and animals. Although some artificial molecular machines have been synthesized and used collectively to perform mechanical tasks, so far there have been no direct measurements of mechanical processes at the single-molecule level. Here we report measurements of the mechanical work performed by a synthetic molecule less than 5 nm long. We show that biased Brownian motion of the sub-molecular components in a hydrogen-bonded [2]rotaxane-a molecular ring threaded onto a molecular axle-can be harnessed to generate significant directional forces. We used the cantilever of an atomic force microscope to apply a mechanical load to the ring during single-molecule pulling-relaxing cycles. The ring was pulled along the axle, away from the thermodynamically favoured binding site, and was then found to travel back to this site against an external load of 30 pN. Using fluctuation theorems, we were able to relate measurements of the work done at the level of individual rotaxane molecules to the free-energy change as previously determined from ensemble measurements. The results show that individual rotaxanes can generate directional forces of similar magnitude to those generated by natural molecular machines.
Perrine Lussis; Tiziana Svaldo-Lanero; Andrea Bertocco; Charles-André Fustin; David A Leigh; Anne-Sophie Duwez
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-8-21
Journal Detail:
Title:  Nature nanotechnology     Volume:  -     ISSN:  1748-3395     ISO Abbreviation:  -     Publication Date:  2011 Aug 
Date Detail:
Created Date:  2011-8-22     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101283273     Medline TA:  Nat Nanotechnol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Department of Chemistry, University of Liège, B6a Sart-Tilman, 4000 Liège, Belgium.
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