Biomacromolecular charge chirality detected using chiral plasmonic nanostructures

Rodier, M., Keijzer, C., Milner, J. , Karimullah, A. S. , Barron, L., Gadegaard, N. , Lapthorn, A. J. and Kadodwala, M. (2020) Biomacromolecular charge chirality detected using chiral plasmonic nanostructures. Nanoscale Horizons, 5, pp. 336-344. (doi: 10.1039/C9NH00525K)

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The charge distributions of solvent exposed surfaces of complex biomolecules such has proteins are unique fingerprints. The chirality of these charge distributions result in stereo-specific electrostatic interactions which help define how proteins interact with each other, contributing to specificity in protein – protein interactions. Thus it is a key concept in understanding chemical processes in biology. There is currently no known spectroscopic phenomenon that allows rapid characterisation of chiral surface charge distributions. We show that this essential property that is currently “invisible” to optical spectroscopy, can be detected by monitoring asymmetries in the chiroptical response of protein-plasmonic nanostructure complexes. The unique capabilities of the phenomenon are utilised to discriminate between a structurally homologous series of proteins, type II dehydroquinase (DHQase) derived from different organisms. The proteins are indistinguishable with conventional structurally sensitive spectroscopy (i.e. circular dichroism). We show that discrimination between proteins can be achieved by detecting differences in chiral surface charge distributions. The phenomenon is explained with a simple model whereby the chiroptical properties of the plasmonic structures are perturbed by the induction of an enantiomeric mirror image charge distribution of the protein in the metal. This new phenomenon has broad impact, it is a powerful analytical tool for discriminating between structurally homologous biomaterials, but will also provide information relevant to macromolecular interactions.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Lapthorn, Dr Adrian and Kadodwala, Professor Malcolm and Keijzer, Dr Chantal and Karimullah, Dr Affar and Barron, Professor Laurence and Milner, Dr Joel and Rodier, Ms Marion and Gadegaard, Professor Nikolaj
Authors: Rodier, M., Keijzer, C., Milner, J., Karimullah, A. S., Barron, L., Gadegaard, N., Lapthorn, A. J., and Kadodwala, M.
College/School:College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
College of Science and Engineering > School of Chemistry
College of Science and Engineering > School of Engineering > Biomedical Engineering
Journal Name:Nanoscale Horizons
Publisher:Royal Society of Chemistry
ISSN (Online):2055-6764
Published Online:01 October 2019
Copyright Holders:Copyright © 2019 The Authors
First Published:First published in Nanoscale Horizons 5:336-344
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
173324Mapping the mesoscale structural landscape using "sculpted" chiral plasmonic fieldsMalcolm KadodwalaEngineering and Physical Sciences Research Council (EPSRC)EP/P00086X/1Chemistry