Fig. 3

PriX NTP-binding residues are necessary for RNA primer synthesis. a Primer synthesis assay on poly(dT) ssDNA for increasing concentrations (125 nM, 250 nM and 500 nM) of wild-type and mutant PriSLX. The reaction products were separated by PAGE under denaturing conditions and detected by phosphorimaging of the incorporated ³²P-αATP. b Primer synthesis assay on mixed-sequence ssDNA 100mer with fixed concentration of wild-type and mutant primase, at 10′ and 40′ time points. The reaction products were separated by denaturing PAGE, stained with SYBR Gold and detected by phosphorimaging. c ATP binding by wild-type and R72A PriX. Binding was measured by fluorescence polarization of fluorescein-labeled ATP in the presence of increasing amounts of primase