RNA replication. The central part of this protein possibly functions as an ATP-binding helicase (Probable). a ribonucleoside 5'-triphosphate + RNA(n) = diphosphate + RNA(n+1) ATP + H2O = ADP + H(+) + phosphate Binds 1 Fe(2+) ion per subunit. Belongs to the potexvirus/carlavirus RNA replication protein family.