The presence of two UvrB subunits in the UvrAB complex ensures damage detection in both DNA strands.
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.
Verhoeven
Esther E A
EE
Laboratory of Molecular Genetics, Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands.
Wyman
Claire
C
Moolenaar
Geri F
GF
Goosen
Nora
N
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D004249:DNA Damage; D004265:DNA Helicases / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D019281:Dimerization; D004706:Endodeoxyribonucleases / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D046911:Macromolecular Substances; D018625:Microscopy, Atomic Force; D009097:Multienzyme Complexes / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011487:Protein Conformation; D021122:Protein Subunits; D013329:Structure-Activity Relationship
D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D009097:Multienzyme Complexes; D021122:Protein Subunits; C058093:UvrB protein, E coli; D004706:Endodeoxyribonucleases; C036385:endodeoxyribonuclease uvrABC; C068631:UvrA protein, E coli; D000251:Adenosine Triphosphatases; D004265:DNA Helicases