Highly potent dUTPase inhibition by a bacterial repressor protein reveals a novel mechanism for gene expression control.
Bottom Line: We found that Φ11 helper phage dUTPase eliminates SaPIbov1 Stl binding to its cognate DNA by binding tightly to Stl protein.Our results disprove the previously proposed G-protein-like mechanism of SaPI transfer activation.We propose that the transfer only occurs if dUTP is cleared from the nucleotide pool, a condition promoting genomic stability of the virulence elements.
Affiliation: Institutes of Enzymology and Organic Chemistry, RCNS, Hungarian Academy of Sciences, Budapest, Hungary email@example.com firstname.lastname@example.org.Show MeSH
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Mentions: We measured the enzymatic activity of dUTPase in the dUTPase:Stl complex and found that Stl exerts highly potent inhibition of dUTPase activity with an IC50 value that approximates the Kd of the protein–protein complex (Figure 2A, Table 1). This inhibition is only observed if dUTPase is pre-incubated with Stl prior to dUTP addition. Such behavior is typical for a slow and tight binding inhibitor (23) and is in excellent agreement with data obtained for the formation of the dUTPase:Stl complex (Figure 1, Table 1) as well as with the previously published kinetics of dUTP binding (20).
Affiliation: Institutes of Enzymology and Organic Chemistry, RCNS, Hungarian Academy of Sciences, Budapest, Hungary email@example.com firstname.lastname@example.org.