University of Toronto, Canada

The molecular dance of a protein allows a chemist’s secret wish to come true.

One fascinating aspect of molecular function is the way information propagates between parts of a molecule that can be many tens of angstroms apart.

Our understanding of how proteins do this, a process termed allostery, emerged from Max Perutz’s pioneering studies of oxygen-carrying haemoglobin. Three-dimensional images show that when a ligand binds to part of the molecule, a discrete set of structural changes take place at distinct sites. This, in turn, influences the ease with which subsequent ligands bind.

Nature has chosen this model in designing many allosteric proteins. However, as a practising nuclear magnetic resonance (NMR) spectroscopist with a strong interest in protein dynamics, I was secretly hoping she might design proteins in which information is communicated through changes in the dynamics between distal sites, with little or no change in overall structure. Moreover, I was rooting for NMR to play a major role in characterizing such a system.

How exciting it was, therefore, to read that Charalampos Kalodimos and his co-workers recently found such a case by studying the motional properties of a protein in different ligated states (N. Popovych et al. Nature Struct. Mol. Biol. 13, 831; 2006). Using NMR spectroscopy, the team quantified protein dynamics for a wide range of timescales. Remarkably, ligand binding at one site is linked to changes in motion far removed, over the complete set of timescales, while a corresponding propagation of structural changes does not occur.

The work of Popovych et al. provides a striking example of the importance of protein dynamics to information transfer. I eagerly await the discovery of more molecular dances and of how they, too, will relate to biological function.