화학공학소재연구정보센터
Process Biochemistry, Vol.50, No.5, 729-737, 2015
Molecular dynamics simulations integrating kinetics for Pb2+-induced arginine kinase inactivation and aggregation
We built a 3D structure of arginine kinase from Exopalaemon carinicauda (ECAK) on the basis of the ORF gene sequence to conduct molecular dynamics simulations between ECAK and Pb2+. As a result, the binding mechanism of Pb2+ to ECAK was predicted from the binding sites, and the structural change was elucidated. To confirm the simulated results, the Pb2+-mediated inhibition and aggregation of ECAK were subsequently conducted. We found that Pb2+ partially inactivated the activity of ECAK with relatively strong binding. The spectrofluorimetry results showed that Pb2+ induced tertiary structural changes of ECAK, with the substantial exposure of hydrophobic surfaces directly induced by ECAK aggregation. The ECAK aggregation process induced by Pb2+ occurred with multi-phase kinetics. The addition of osmolytes did not protect ECAK from PI? inactivation. Because AK plays an important role in the cellular energy metabolism of invertebrates, our study suggests new information about the effect of Pb2+ on ECAK's enzymatic function and unfolding, including aggregation, which may be toxic to invertebrates or may act as a negative regulator. (C) 2015 Elsevier Ltd. All rights reserved.