Molecular dynamics simulation integrating study for Cr super(3+)-binding to arginine kinase

We simulated the 3D structure of arginine kinase from Exopalaemon carinicauda (ECAK) on the basis of homology modeling. Computational molecular dynamics simulations between ECAK and Cr super(3+) were conducted to elucidate the functional role of Cr super(3+) on ECAK structure and catalysis. As a result, the binding mechanism of Cr super(3+) to ECAK along with binding sites and structural changes were predicted. To confirm the simulation results, kinetic studies of Cr super(3+)-mediated aggregation of ECAK were subsequently conducted. We found that Cr super(3+) significantly induced ECAK aggregation with a multi-phase kinetic process at a high dose of Cr super(3+). The spectrofluorimetric results showed that Cr super(3+)-induced tertiary structural changes in ECAK caused extensive exposure of hydrophobic surfaces, which could be a triggering factor for inducing ECAK aggregation. Our study provides new information concerning the effect of Cr super(3+) on ECAK's enzymatic function and unfolding, including aggregation, which might be toxic or act as a negative regulator.