<p>(A) The capacity of the ϕDI, ϕO11, ϕPhi55 and ϕDII dimeric Duts to form a complex with Stl was checked by Native-PAGE maintaining a constant amount of Dut proteins (17 μM) and identical or double concentrations of Stl. (B) Binding of Stl inhibits dUTPase activity. The enzymatic activity of the inducer dimeric Duts ϕDI and ϕO11 were inhibited by Stl whereas it was not affected for the non-inducer allelic variants ϕ55 and ϕDII even though a 10-fold excess of Stl was used (left panels). The dUTPase activity is inhibited by Stl in a dosage dependent manner for ϕDI and ϕO11 Duts (right panels). Average and standard deviation of six replicates are shown.</p