Collaborative dynamic DNA scanning by nucleotide excision repair proteins investigated by single- molecule imaging of quantum-dot-labeled proteins.
How DNA repair proteins sort through a genome for damage is one of the fundamental unanswered questions in this field. To address this problem, we uniquely labeled bacterial UvrA and UvrB with differently colored quantum dots and visualized how they interacted with DNA individually or together using oblique-angle fluorescence microscopy. UvrA was observed to utilize a three-dimensional search mechanism, binding transiently to the DNA for short periods (7 s). UvrA also was observed jumping from one DNA molecule to another over approximately 1 microm distances. Two UvrBs can bind to a UvrA dimer and collapse the search dimensionality of UvrA from three to one dimension by inducing a substantial number of UvrAB complexes to slide along the DNA. Three types of sliding motion were characterized: random diffusion, paused motion, and directed motion. This UvrB-induced change in mode of searching permits more rapid and efficient scanning of the genome for damage.
Department of Biological Sciences, University of Essex, Colchester, Essex CO4 3SQ, UK. nkad@essex.ac.uk
Neil M
NM
Kad
Hong
H
Wang
Guy G
GG
Kennedy
David M
DM
Warshaw
Bennett
B
Van Houten
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D001665:Binding Sites; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004265:DNA Helicases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D045663:Quantum Dots
D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C058093:UvrB protein, E coli; D000255:Adenosine Triphosphate; D004247:DNA; C068631:UvrA protein, E coli; D000251:Adenosine Triphosphatases; D004265:DNA Helicases