Molecular simulations reveal a new entry site in quercetin 2,3-dioxygenase. A pathway for dioxygen?

Molecular dynamics simulations performed on quercetin 2,3-dioxygenase have shown the existence of a channel linking the bulk solvent and the cavity of the enzyme. Although much is known about the the oxygenolysis reaction catalyzed by this enzyme, the way dioxygen enters the active site has not been firmly established. The size, orientation and hydrophobic character of this channel suggests that it could provide an entrance for molecular dioxygen into the cavity. Free energy calculations show that such a process is likely to occur.