Download Nanoscale localisation of a Candida albicans peptide

Nanoscale localisation of a Candida albicans peptide-toxin on cell
membranes by TERS
Ludovic Roussille1, Annika Franke2, Selene Mogavero, Bernhard Hube2, and Volker Deckert1
1
Leibniz Institute of Photonic Technology (IPHT), Albert-Einstein-Str. 9, 07745 Jena, Germany
Institute of Physical Chemistry and Abbe center of Photonics, Friedrich Schiller University
Lessingstrasse 10, 07743 Jena, Germany
2
Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and
Infection Biology (HKI), Beutenbergstrasse 11a, 07745 Jena Germany
How to localize a protein on a cell membrane?
Cell membranes incorporate many proteins of different size. In order to directly differentiate between
different proteins, the molecule of interest is usually specifically labeled. However, if the protein is
only a small peptide, like the Candida albicans peptide-toxin Candidalysin which is only 31 amino acids
long [1], any molecule or nanoparticle used to label the peptide will substantially increase its size.
Consequently it might deeply affect the actual peptide function.
AFM-TERS is based on the creation of a local plasmon at the apex of a scanning microscopy tip, which
leads to an enhanced Raman signal. While it is challenging to discriminate between different proteins
directly, Raman spectroscopy is very sensitive to the change of a hydrogen by a deuterium. Hence,
deuteration is a promising alternative to label such a small peptide and maintain its function.
Candidalysin is a peptide secreted by C. albicans, which has been shown to be responsible for host
cells damage. However, the respective mechanism remains unclear. Therefore, nanometer scale
localization of the peptide, and potential simultaneous structural change determination, will be
essential to gain a better understanding of the actual mechanism. Our data show first TERS
measurements that potentially allow such a high resolution analysis. We were able to detect the
presence of deuterated Candidalysin by AFM-TERS on cells, which directly implies the presence of the
peptide in/on the cell membrane.
Fig1: AFM image of an epithelial cell destroyed by incubation with deuterated Candidalysin.
[1] Moyes et al, Nature 532 (2016) 64-68
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