PROTEIN DYNAMICS

Protein dynamics reveals the complexity of these biomolecules. The str uctural fluctuations and relaxations are determined by a rugged energy landscape where the vallies, the conformational substates, are arrang ed in a hierarchy of tiers. Several experimental techniques have been used to study the different aspects of protein dynamics. We discuss X- ray structure determinations and pressure tuned hole burning experimen ts to study structural distributions. Equilibrium fluctuations have be en studied by Mossbauer spectroscopy, Rayleigh scattering of Mossbauer radiation and incoherent neutron scattering. Most results on structur al relaxations have been obtained from the CO rebinding kinetics in CO ligated myoglobin after flash-photolysis. In addition some Mossbauer investigations of structural relaxation are discussed.