Effect of magnesium ions on the thermal stability of human poly(A)-specific ribonuclease

Poly(A)-specific ribonuclease (PARN), a member of the DEDD family, is a key enzyme involved in the deadenylation of mRNA in higher eukaryotic cells. In this research, it was found that Mg2+ could protect PARN against thermal inactivation by increasing the midpoint of inactivation and decreasing the inactivation rate. This protective effect was unique to Mg2+ in a concentration-dependent manner. However, the thermal unfolding and aggregation was promoted by the addition of Mg2+ at high temperatures. These results revealed that Mg2+ might have dual effects on PARN stability: protecting the active site but endangering the overall structural stability.