AUTHOR=La Penna Giovanni , Chelli Riccardo TITLE=Structural Insights into the Osteopontin-Aptamer Complex by Molecular Dynamics Simulations JOURNAL=Frontiers in Chemistry VOLUME=6 YEAR=2018 URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2018.00002 DOI=10.3389/fchem.2018.00002 ISSN=2296-2646 ABSTRACT=

Osteopontin is an intrinsically disordered protein involved in tissue remodeling. As a biomarker for pathological hypertrophy and fibrosis, the protein is targeted by an RNA aptamer. In this work, we model the interactions between osteopontin and its aptamer, including mono- (Na+) and divalent (Mg2+) cations. The molecular dynamics simulations suggest that the presence of divalent cations forces the N-terminus of osteopontin to bind the shell of divalent cations adsorbed over the surface of its RNA aptamer, the latter exposing a high negative charge density. The osteopontin plasticity as a function of the local concentration of Mg is discussed in the frame of the proposed strategies for osteopontin targeting as biomarker and in theranostic.