Protein Beta (354 aa) is encoded in the left-end nonessential gop-beta operon of satellite bacteriophage P4 and contains a calcineurin-like phosphoesterase superfamily domain (DUF2075/PF09848). Cotranscribed with gop, Beta counteracts the lethal host-killing activity of the Gop protein in Escherichia coli, functioning as the antitoxin/inhibitory partner of the Gop-Beta module.
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Download this section (compressed HTML)Q: Does P4 Beta directly bind Gop to form a toxin-antitoxin complex, or does its DUF2075 calcineurin-like phosphoesterase domain hydrolyze a nucleotide second messenger or reverse a Gop-catalyzed modification?
Suggested experts: Gianni Dehò, Daniela Ghisotti, Eduardo P. C. Rocha
Experiment: Co-express and purify His-tagged Beta and untagged Gop from Escherichia coli to test direct complex formation by size-exclusion chromatography and assay metal-dependent phosphoesterase activity of Beta on cyclic oligonucleotides and phosphopeptides.
Hypothesis: Beta forms a stable heteromeric complex with Gop that masks Gop's toxic effector activity until triggered by heterologous phage infection.
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