Role of structural ions on the dynamics of the Pseudomonas fluorescens 07A metalloprotease.

The molecular dynamics of the Pseudomonas fluorescens 07A metalloprotease in the presence of structural Ca and Mn ions was evaluated. Seven Ca ions are primarily bound to the C-terminus, while a divalent cation is located at the catalytic site, acting as a cofactor. The observed enzyme's experimental activity suggests that Mn could compete for the active site of the enzyme with Ca, Zn or other divalent cations, thus providing greater catalytic power to the enzyme. Our molecular dynamics simulations suggest that these ions partially protect the enzyme's structure from thermal denaturation. Moreover, our simulations have shown a collective movement of opening-closing of the active-site in simulations with structural Ca and Mn ions bound, leading to a proposal of a dynamical model of P. fluorescens 07A metalloprotease active and inactive conformations. These findings can support the development of measures to control the activity of P. fluorescens and other spoilage microorganism proteases.