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Protein–protein interaction between monomers of coliphage HK022 excisionase
Author(s) -
Gottfried Pnina,
Kolot Mikhail,
Silberstein Nava,
Yagil Ezra
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2004.09.045
Subject(s) - coliphage , cooperativity , dna , chemistry , monomer , cooperative binding , binding site , in vitro , bacteriophage , plasma protein binding , biochemistry , biophysics , biology , gene , escherichia coli , organic chemistry , polymer
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.