In chemical reactions, left and right can make a big difference. A
"left-handed" molecule of a particular chemical composition could be an
effective drug, while its mirror-image "right-handed" counterpart could
be completely inactive.
That's because, in biology, "left" and "right"
molecular designs are crucial: Living organisms are made only from
left-handed amino acids. So telling the two apart is important—but
difficult.
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| Electron microscopy "maps" of octahedral gold nanoparticles surrounded by cubic silver shells. Attaching a biomolecule (e.g., DNA) to these nanoparticles strengthens a signal representing a difference between left- and right-handed molecules' response to light by 100 times, and pushes it toward the visible range of the electromagnetic spectrum. (Credit: Image courtesy of Brookhaven National Laboratory) |
Credit: http://www.bnl.gov