Study of dephosphorylated 2'-5'-linked oligoadenylates impact on apo-S100A1 protein conformation by heteronuclear NMR and circular dichroism.

Low molecular weight natural mediators, 2'-5'-linked oligoadenylates, play an important role in interferon-based antiviral mechanism; participate in growth, apoptosis and other important cellular processes. Taking into account their concentration within living cells, the 2'-5'A3 oligoadenylates may act as additional biologically active substrates, capable of regulating the S100A1 protein functioning in vivo. Aim. Find the evidence for the interaction of human apo-S100A1 with 2'-5'-linked oligoadenylates. Methods. Using the circular dichroism (CD) and heteronuclear NMR spectroscopy. Results. The obtained results demonstrated the occurrence of the secondary structure changes in human S100A1 protein upon the interaction with 2'-5'-linked oligoadenylates as well as indicated specific residues involved in this process. Conclusions. Our study points to the 2'-5'-linked oligoadenylates as possible additional elements of the complex system of fine regulation of the Ca2+-signal transduction pathway in human cells. [ABSTRACT FROM AUTHOR]