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Eco RII: a restriction enzyme evolving recombination functions?
Author(s) -
Mücke Merlind,
Grelle Gerlinde,
Behlke Joachim,
Kraft Regine,
Krüger Detlev H.,
Reuter Monika
Publication year - 2002
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdf514
Subject(s) - biology , recombination , genetics , restriction enzyme , enzyme , computational biology , dna , gene , biochemistry
The restriction endonuclease Eco RII requires the cooperative interaction with two copies of the sequence 5′CCWGG for DNA cleavage. We found by limited proteolysis that Eco RII has a two‐domain structure that enables this particular mode of protein–DNA interaction. The C‐terminal domain is a new restriction endonuclease, Eco RII‐C. In contrast to the wild‐type enzyme, Eco RII‐C cleaves DNA specifically at single 5′CCWGG sites. Moreover, substrates containing two or more cooperative 5′CCWGG sites are cleaved much more efficiently by Eco RII‐C than by Eco RII. The N‐terminal domain binds DNA specifically and attenuates the activity of Eco RII by making the enzyme dependent on a second 5′CCWGG site. Therefore, we suggest that a precursor Eco RII endonuclease acquired an additional DNA‐binding domain to enable the interaction with two 5′CCWGG sites. The current Eco RII molecule could be an evolutionary intermediate between a site‐specific endonuclease and a protein that functions specifically with two DNA sites such as recombinases and transposases. The combination of these functions may enable Eco RII to accomplish its own propagation similarly to transposons.