Organized but intermittent: a liquid mimicking disordered proteins

Proteins, the engines of life, form the basis for all vital functions in all living systems. Most commonly, the biological functions of the proteins are imposed by their well-defined structures. This is not the case, however, for the so-called intrinsically disordered proteins (IDP), which e.g. are involved in DNA repair. In IDPs, the structural motifs are labile, rapidly fluctuating between conformations, which makes them very challenging to study.

The Theory of Condensed Matter and Optical Condensed Matter Physics groups (both Zernike Institute for Advanced Materials) together with colleagues from the University of Amsterdam joined efforts to mimic the properties of IDPs with a liquid consisting of the building block of proteins, the molecule N-methylacetamide (NMA). The dynamical properties of NMA were studied using combined computational and experimental ultrafast spectroscopy, which probes fast phenomena from a femto- to the pico-second timescale. Surprisingly, NMA molecules interacting via hydrogen bonds form fragile transient chain-like structures, which have been identified from their unique spectroscopic signature. Our ability to distinguish such chains provides the excellent potential for identifying similar organized but intermittent structures in IDPs.

The results of this work are published in the Journal of Physical Chemistry Letters (A. V. Cunha, E.  Salamatova, R. Bloem, S. Roeters, S. Woutersen, M. S. Pshenichnikov, and T.L.C Jansen, “Interplay Between Hydrogen Bonding and Vibrational Coupling in Liquid N-Methylacetamide”, J. Phys. Chem. Lett., 2017, 8, 2438–2444 DOI: 10.1021/acs.jpclett.7b00731

http://pubs.acs.org/doi/abs/10.1021/acs.jpclett.7b00731).

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