Forthcoming Events

23.01.2019 - 25.01.2019, DESY-Hamburg and European XFEL, Schenefeld, Germany
09.02.2019 - 13.02.2019, Banff Centre, Alberta, Canada

Peter Hamm

December 18, 2009

Peter Hamm, Professor of Physical Chemistry, University of Zurich received an ERC Advance Grant in "Physical Sciences and Engineering".

DYNALLO: Towards a Dynamical Understanding of Allostery

Allostery is a fundamental concept Nature uses to regulate the affinity of a certain substrate to an active site of a protein by binding a ligand to a distant allosteric site. Within this project, experimental tools are designed to gain an atomistic, dynamical understanding of the conformational transitions that give rise to allostery. The problem is approached from two distinctively different directions:
  • Tools are developed to initiate conformational transitions of proteins that per se are not photoswitchable, in order to mimic allosteric transitions. To that end, two amino acid side chains of an allosteric protein are crosse-linked with a photo-switchable azobenzene-moiety to initiate a conformational transition similar to ligand binding. Ultrafast infrared spectroscopy, augmented with isotope and chemical labelling, is employed to time-resolve the conformational transition.
  • Furthermore, a frequently expressed hypothesis will be experimentally tested, according to that allosteric and active site communicate by exchange of vibrational energy. To that end, versatile approaches are designed that allow one to locally deposit vibrational energy at essentially any site in a protein (e.g. through pumping of an optical chromophore that undergoes ultrafast internal conversion), and to detect its appearance at any other site by using vibrational transitions as local thermometers. Thereby, a network of connectivity in a given protein can be mapped out.
In order to merge the two approaches, both are applied to one and the same protein family. One concrete example are PDZ domains, which are among the smallest allosteric proteins, and for which the connection between allostery and vibrational energy flow has been made explicit, based on computer simulations. This hypothesis will eventually be tested experimentally, and provide the foundation for a description of allostery that is on an equal footing as our current understanding of protein folding.

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