The search for large parity-violating energy differences finds fruit in thiosubstituted DNA analogues

✍ Scribed by A.J. MacDermott; G.E. Tranter; S.J. Trainor

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 301 KB
• Volume: 194
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(92)85525-f

✦ Synopsis

Eadier calculations of parity-violating energy differences between enantiomers (PVEDs) have produced values for typical biomolecules no larger than 10 -20 hartree, corresponding to 10 -17 kT at 298 K, but in this paper we report PVEDs of 10 -17 hartree, corresponding to 10-t4 kT, for thiosubstituted DNA analogues.

Left-and right-handed chiral molecules have been classically regarded as exact mirror images and therefore energetically equivalent. However it is now known that they are in fact energetically inequivalent [ 1,2 ] due to parity-violating weak neutral current interactions (mediated by the Z ° boson) between electrons and neutrons. The weak interaction imparts a small "parity-violating energy shift" (PVES), Epv, to the energy of a chiral molecule, and a similar shift, -Epv, of equal magnitude but opposite sign, to the energy of its enantiomer, giving a "parity-violating energy difference" (PVED) AEpv = 2Epv between enantiomers. This results in an enantiomeric excess of the more stable enantiomer given