Physical and Chemical Models for the Origin of Biological Homochirality


Wednesday, April 17, 2013, 4:00pm


Geo Museum, 24 Oxford Street, Haller Hall, Rm. 102, Cambridge, MA

Donna Blackmond (Professor of Chemistry - The Scripps Research Institute)

The property of chirality has fascinated scientists and laymen alike since Pasteur’s first painstaking separation of the enantiomorphic crystals of a tartrate salt over 150 years ago. Chiral molecules – nonsuperimposable forms that are mirror images of one another, as are left and right hands – in living organisms in Nature exist almost exclusively as single enantiomers, as exemplified by D-sugars and L-amino acids. Single chirality is critical for molecular recognition and replication processes and would thus seem to be a a signature of life. Yet left and right-handed molecules of a compound will form in equal amounts (a racemic mixture) when we synthesize them in the laboratory in the absence of some type of directing template. Our work has led to the development of several plausible mechanisms for how one enantiomer might have come to dominate over the other in the prebiotic world, highlighting mechanisms for enantioenrichment by either chemical or physical processes.

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