Protein-protein interaction between monomers of coliphage HK022 excisionase

Pnina Gottfried, Mikhail Kolot, Nava Silberstein, Ezra Yagil*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Excisionase (Xis) is an accessory protein that is required for the site-specific excision reaction of the coliphages HK022 and λ. Xis binds in a strong cooperative manner to two tandem binding sites (X1 and X2) located on the P arm of the attachment (att) sites on the phage genome. As a result of crosslinking experiments in vivo and in vitro of Xis-overexpressing cells, by gel filtration of purified Xis and by FRET analyses we show that Xis monomers of HK022 interact and form dimers that are not dependent on the single Cys residue of the protein and on the presence of DNA. The formation of the dimers may explain the strong binding cooperativity of Xis to its sites on DNA.

Original languageEnglish
Pages (from-to)17-20
Number of pages4
JournalFEBS Letters
Issue number1-2
StatePublished - 5 Nov 2004


FundersFunder number
Israel Academy of Sciences and Humanities637/02
Israel Science Foundation


    • DSG, disuccinimidyl glutarate
    • DSS, disuccinimidyl suberate
    • FITC, fluorescein-5-isothiocyanate
    • FRET, fluorescence resonance energy transfer
    • TRITC, tetramethylrhodamine-5- (and 6) isothiocyanate
    • bp, base pairs
    • β-ME, β-mercaptoethanol


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