Energy landscapes: some new horizons.

Kinetic transition networks can now be calculated for small proteins using geometry optimisation to characterise minima, transition states and pathways, and unimolecular rate theory to supply rate constants corresponding to each transition state. The networks can be visualised by constructing disconnectivity graphs, revealing striking differences between good structure-seeking systems and a model glass former. The glassy landscape contains competing low-lying minima separated by high barriers, providing a more extreme example of the frustration previously characterised for model proteins. Free energy projections that preserve barriers and rates can be obtained from the network representation, and global kinetics can be addressed on the experimental time scale.