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The presence of two UvrB subunits in the UvrAB complex ensures damage detection in both DNA strands
Author(s) -
Verhoeven Esther E.A.,
Wyman Claire,
Moolenaar Geri F.,
Goosen Nora
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/cdf396
Subject(s) - dna , dna damage , nucleotide excision repair , monomer , dimer , protein subunit , biology , dna repair , nucleotide , pyrimidine dimer , escherichia coli , biophysics , microbiology and biotechnology , biochemistry , chemistry , gene , polymer , organic chemistry
It is generally accepted that the damage recognition complex of nucleotide excision repair in Escherichia coli consists of two UvrA and one UvrB molecule, and that in the preincision complex UvrB binds to the damage as a monomer. Using scanning force microscopy, we show here that the damage recognition complex consists of two UvrA and two UvrB subunits, with the DNA wrapped around one of the UvrB monomers. Upon binding the damage and release of the UvrA subunits, UvrB remains a dimer in the preincision complex. After association with the UvrC protein, one of the UvrB monomers is released. We propose a model in which the presence of two UvrB subunits ensures damage recognition in both DNA strands. Upon binding of the UvrA 2 B 2 complex to a putative damaged site, the DNA wraps around one of the UvrB monomers, which will subsequently probe one of the DNA strands for the presence of a lesion. When no damage is found, the DNA will wrap around the second UvrB subunit, which will check the other strand for aberrations.