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Proc Natl Acad Sci U S A. 2017 Mar 7;114(10):2474-2478. doi: 10.1073/pnas.1611467114. Epub 2017 Feb 22.

Chirality-induced spin polarization places symmetry constraints on biomolecular interactions.

Author information

1
Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
2
Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
3
Evogene Ltd., Rehovot 76121, Israel.
4
Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260.
5
Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel; ron.naaman@weizmann.ac.il.

Abstract

Noncovalent interactions between molecules are key for many biological processes. Necessarily, when molecules interact, the electronic charge in each of them is redistributed. Here, we show experimentally that, in chiral molecules, charge redistribution is accompanied by spin polarization. We describe how this spin polarization adds an enantioselective term to the forces, so that homochiral interaction energies differ from heterochiral ones. The spin polarization was measured by using a modified Hall effect device. An electric field that is applied along the molecules causes charge redistribution, and for chiral molecules, a Hall voltage is measured that indicates the spin polarization. Based on this observation, we conjecture that the spin polarization enforces symmetry constraints on the biorecognition process between two chiral molecules, and we describe how these constraints can lead to selectivity in the interaction between enantiomers based on their handedness. Model quantum chemistry calculations that rigorously enforce these constraints show that the interaction energy for methyl groups on homochiral molecules differs significantly from that found for heterochiral molecules at van der Waals contact and shorter (i.e., ∼0.5 kcal/mol at 0.26 nm).

KEYWORDS:

biorecognition; chirality; enantioselectivity; exchange interaction; spin

PMID:
28228525
PMCID:
PMC5347616
DOI:
10.1073/pnas.1611467114
[Indexed for MEDLINE]
Free PMC Article

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