Revitalizing an important field in biophysics: The new frontiers of molecular crowding

Abstract

Taking into account the presence of the crowded environment of a macromolecule has been an important goal of biology over the past 20 years. Molecular crowding affects the motions, stability and the kinetic behaviour of proteins. New powerful approaches have recently been developed to study molecular crowding, some of which make use of the synchrotron radiation light. The meeting "New Frontiers in Molecular Crowding" was organized in July 2022at the European Synchrotron Radiation facility of Grenoble to discuss the new frontiers of molecular crowding. The workshop brought together researchers from different disciplines to highlight the new developments of the field, including areas where new techniques allow the scientists to gain unprecedently expected information. A key conclusion of the meeting was the need to build an international and interdisciplinary research community through enhanced communication, resource-sharing, and educational initiatives that could let the molecular crowding field flourish further.

Keywords: biochemistry; biophysics; crowding; phase separation; synchrotron radiation; x-ray correlation spectroscopy.

FIGURE 1

Cartoon of the crowded interior of an Escherichia coli cell. The test protein molecule (red) is in the cytoplasm exterior to the nucleoid, consisting of primarily soluble proteins, ribonucleic acids, and macromolecular assemblies such as ribosomes and proteasomes. Nonspecific interactions between the test protein and their immediate surroundings within a medium as heterogeneous and highly volume occupied as the bacterial cytoplasm can significantly influence the equilibria and rates of reactions (i.e., self- and hetero-associations) in which the test protein participates. Figure from Goodsell (http://mgl.scripps.edu/people/goodsell/illustration/public).

FIGURE 2

Aerial view of ESRF; the orange oval indicates the location of the new beamline devoted to the use of coherent x-rays currently under construction. Coherent x-rays have laser-like properties and produce speckle patterns when they illuminate disordered systems such as a protein solution. An example of speckle pattern is shown in the central part of the image. Since the speckle pattern encodes the position of each scatterer, they can be used to measure diffusion dynamics.