Ions Everywhere? Mg in the μ-Opioid GPCR and Atomic Details of Their Impact on Function.

Filizola and co-workers have applied a combination of long-time molecular dynamics and oscillating chemical potential grand canonical Monte Carlo/molecular dynamics to investigate the distribution of Mg and Na in the μ-opioid receptor and their impact on its function. Results indicate atomic details of potential mechanisms by which Mg leads to increased efficacy of opioid analgesics. The presence of information flow between the extracellular loops and the intracellular region of the G-protein-coupled receptors that interacts with G-proteins in the presence of Mg may be a phenomenon occurring in other G-protein-coupled receptors and, therefore, potentially of broad impact.