Cavities and packing defects in the structural dynamics of myoglobin
AUTOR(ES)
Brunori, Maurizio
FONTE
Oxford University Press
RESUMO
Small globular proteins contain internal cavities and packing defects that reduce thermodynamic stability but seem to play a role in controlling function by defining pathways for the diffusion of the ligand/substrate to the active site. In the case of myoglobin (Mb), a prototype for structure–function relationship studies, the photosensitivity of the adduct of the reduced protein with CO, O2 and NO allows events related to the migration of the ligand through the matrix to be followed. The crystal structures of intermediate states of wild-type (wt) and mutant Mbs show the photolysed CO to be located either in the distal heme pocket (primary docking site) or in one of two alternative cavities (secondary docking sites) corresponding to packing defects accessible to an atom of xenon. These results convey the general picture that pre-existing internal cavities are involved in controlling the dynamics and reactivity of the reactions of Mb with O2 and other ligands, including NO.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1083996Documentos Relacionados
- The role of cavities in protein dynamics: Crystal structure of a photolytic intermediate of a mutant myoglobin
- Protein dynamics: hydration and cavities
- Water in channel-like cavities: structure and dynamics.
- The role of structure, energy landscape, dynamics, and allostery in the enzymatic function of myoglobin
- Nonexponential protein relaxation: dynamics of conformational change in myoglobin.