Molecular analysis of plasmid DNA repair within ultraviolet-irradiated Escherichia coli. II. UvrABC-initiated excision repair and photolyase-catalyzed dimer monomerization

In this study, a novel approach to the analysis of DNA repair in Escherichia coli was employed which allowed the first direct determination of the mechanisms by which endogenous DNA repair enzymes encounter target sites in vivo. An in vivo plasmid DNA repair analysis was employed to discriminate bet...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 1988-09, Vol.263 (25), p.12738-12743
Main Authors: Gruskin, E A, Lloyd, R S
Format: Article
Language:English
Subjects:
Biological and medical sciences
Deoxyribodipyrimidine Photo-Lyase - metabolism
Deoxyribonuclease (Pyrimidine Dimer)
DNA Repair
DNA, Bacterial - metabolism
DNA, Bacterial - radiation effects
Electrophoresis, Agar Gel
Endodeoxyribonucleases - metabolism
Escherichia coli - genetics
Escherichia coli - radiation effects
Escherichia coli Proteins
Fundamental and applied biological sciences. Psychology
Kinetics
Lyases - metabolism
Molecular and cellular biology
Molecular genetics
Mutagenesis. Repair
Mutation
Plasmids
Pyrimidine Dimers - metabolism
Ultraviolet Rays
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In this study, a novel approach to the analysis of DNA repair in Escherichia coli was employed which allowed the first direct determination of the mechanisms by which endogenous DNA repair enzymes encounter target sites in vivo. An in vivo plasmid DNA repair analysis was employed to discriminate between two possible mechanisms of target site location: a processive DNA scanning mechanism or a distributive random diffusion mechanism. The results demonstrate that photolyase acts by a distributive mechanism within E. coli. In contrast, UvrABC-initiated excision repair occurs by a limited processive DNA scanning mechanism. A majority of the dimer sites on a given plasmid molecule were repaired prior to the dissociation of the UvrABC complex. Furthermore, plasmid DNA repair catalyzed by the UvrABC complex occurs without a detectable accumulation of nicked plasmid intermediates despite the fact that the UvrABC complex generates dual incisions in the DNA at the site of a pyrimidine dimer. Therefore, the binding or assembly of the UvrABC complex on DNA at the site of a pyrimidine dimer represents the rate-limiting step in the overall process of UvrABC-initiated excision repair in vivo.
ISSN:0021-9258
1083-351X
DOI:10.1016/S0021-9258(18)37815-3