Figure 2.

Primase activities of human PrimPol and PrimPol^Y89D. (A) Human PrimPol has primase activity and can produce de novo primers using rNTPs and dNTPs in a homo-polymer template-dependent fashion. (B) PrimPol^Y89D partially loses its primase activity. This variant of PrimPol cannot synthesize RNA primers but is an active primase utilizing dNTPs. (C) PrimPol^Y89S shows significant loss of the enzymatic activity with residual primase activity observed in presence of dNTPs. (D) PrimPol^Y89F is an active primase variant capable of synthesizing both RNA and DNA primers with efficiency comparable to wild-type PrimPol.