Disease relevance of ECs5040

• Excision in Escherichia coli is accomplished by three proteins designated UvrA, UvrB, and UvrC [1].
• The biological activity of nonreplicating UV-irradiated phage DNA declined with time after infection of uvrA cells; this decline was photoproduct-dependent, more marked for undermethylated than overmethylated phage DNA, and depended on host MutHLS functions [2].
• Localization of UvrA and effect of DNA damage on the chromosome of Bacillus subtilis [3].
• Microinjection of Escherichia coli UvrA, B, C and D proteins into fibroblasts of xeroderma pigmentosum complementation groups A and C does not result in restoration of UV-induced unscheduled DNA synthesis [4].
• Haemophilus influenzae UvrA: overexpression, purification, and in cell complementation [5].

High impact information on ECs5040

• UvrA, the component that binds directly to the DNA, and UvrB, which attaches itself to the UvrA-DNA complex, both contain consensus sequences though to be diagnostic of ATP-binding sites, although the UvrC sequence does not [6].
• E. coli uvrB protein binds to DNA in the presence of uvrA protein [7].
• The Mfd protein was shown to (i) displace RNAP stalled at a lesion in an adenosine triphosphate-dependent reaction, (ii) bind to the damage recognition subunit (UvrA) of the excision nuclease, and (iii) stimulate the repair of the transcribed strand only when transcription is taking place [8].
• 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 [9].
• This ABC 3' exonuclease activity depends on higher concentrations of Uvr proteins as compared with dual incision and may be relevant to reactions that occur when UvrA and UvrB are increased during SOS induction [10].

Chemical compound and disease context of ECs5040

• To study the activity of the Escherichia coli UvrA and UvrB nucleotide excision repair proteins during the formation of the pre-incision complex at a damaged DNA site, we used substrates with modifications around a single 2-(acetylamino)fluorene (AAF) lesion [11].
• The purified gene product causes the nicking of DNA at the 8th phosphodiester bond 5' and the 5th phosphodiester bond 3' to a thymine dimer when mixed with E. coli UvrA and UvrB proteins and a DNA substrate containing a uniquely located thymine dimer [12].
• Escherichia coli UvrA, UvrB and UvrC proteins acting in concert remove the major ultraviolet light-induced photoproduct, the pyrimidine dimer, from DNA in the form of a 12 to 13-nucleotide long single-stranded fragment [13].
• Native and denaturing polyacrylamide gel electrophoresis was used to show the formation of ternary coordination complexes between the metal-treated 49-bp DNA fragment and the Escherichia coli UvrA and UvrB DNA repair proteins [14].
• The DrrC protein of Streptomyces peucetius, a UvrA-like protein, is a DNA-binding protein whose gene is induced by daunorubicin [15].

Biological context of ECs5040

• The supercoiling activity of UvrAB on UV-damaged DNA was also studied using UV-damaged plasmid DNA and a mutant UvrA protein that lacks the 40 C-terminal amino acids and is defective in preferential binding to UV-damaged DNA [16].
• However, if the free ditercalinium concentration is maintained to allow the intercalation of one molecule of ditercalinium per 3000 base pairs, the half-life of the UvrA- or UvrAB-ditercalinium-DNA complex is 50 min, comparable to that of the complex of UvrAB proteins formed with pyrimidine dimer-containing DNA [17].
• There are several preincision steps governed by this pathway, which includes an ATP-dependent UvrA dimerization reaction required for UvrAB nucleoprotein formation [18].
• This implies that the N-terminal zinc-finger of UvrA doesn't play a direct role in its interactions with UvrB and DNA [19].
• Thus, both ATP binding and hydrolysis are required for the damage recognition step enabling UvrA to discriminate between damaged and undamaged sites on DNA [20].

Anatomical context of ECs5040

• Construction of deletion mutants of the Escherichia coli UvrA protein and their purification from inclusion bodies [21].
• Introduction of this hybrid gene into simian cos-1 cells results in the synthesis of a full length UvrA protein (114 kD) which has retained its ability to bind to single-stranded DNA [22].

Associations of ECs5040 with chemical compounds

• Under conditions of saturating UvrB protein approximately one UvrB molecule binds to DNA per damaged site in a reaction that requires catalytic amounts of UvrA subunit [23].
• A number of other intercalators, including acriflavin and ethidium bromide, appear to inhibit the excinuclease by a similar mechanism--that is, by trapping the UvrA subunit in nonproductive complexes on undamaged DNA [24].
• In addition the binding of the UvrA and UvrB subunits to the damaged substrate caused the 11th phosphodiester bond 5' to the psoralen-modified thymine to become hypersensitive to DNase I cleavage [25].
• In contrast, adenosine 5'-O-(thiotriphosphate) increases nonspecific binding and completely abolishes the UvrA footprint [26].
• Analysis of a 5' prenicked cholesterol substrate revealed that the second 5' incision is efficiently produced by UvrBC independent of UvrA [27].

Physical interactions of ECs5040

• The UvrA protein is the DNA binding and damage recognition subunit of the damage-specific UvrABC endonuclease [28].

Other interactions of ECs5040

• UvrA protein is a major component of ABC endonuclease complex involved in nucleotide excision repair (NER) mechanism [5].

Analytical, diagnostic and therapeutic context of ECs5040

• We have analysed the structural properties of the different protein-DNA complexes formed by UvrA, UvrB and (damaged) DNA using atomic force microscopy [29].
• Gel mobility shift assays indicated that this substrate supported UvrA dissociation from the UvrB-DNA complex, which led to efficient incision [30].
• To study the potential roles of both helix-turn-helix and zinc finger motifs in the functioning of UvrA protein, random mutations were created in these motif regions by degenerate oligonucleotide-directed mutagenesis [31].
• We thus conclude that the two zinc fingers identified by sequence analysis do indeed have zinc finger structure in UvrA protein [32].
• Co-immunoprecipitation assays showed that DnaK bound denatured UvrA in the absence of ATP [33].

References