SRPK1 and SRPK2 do not have additive effect on CpWT capsid phosphorylation.

(A) Purification of His-CpWT. His-CpWT were purified using Ni-NTA affinity chromatography in the presence 6M urea. Samples were resolved by SDS-PAGE. (B) GuHCl was removed by dialysis to allow His-CpWT to assemble into capsids. The capsids were further purified by gel filtration. Protein collected from the peak fractions was analyzed by SDS-PAGE. (C) In vitro radioactive kinase assay was performed using the CpWT capids in the presence of SRPK1WT or SRPK2WT or both kinases. Samples were analyzed by SDS-PAGE and autoradiography. Presence of both SRPK1 and SRPK2 did not result in more phosphorylated Cp product. (TIF)